I. Historical development A. Scientists 1. Bertillon s anthropometry a. Body measurements to distinguish between people

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1 I. Historical development A. Scientists 1. Bertillon s anthropometry a. Body measurements to distinguish between people Anthropological Analysis of bones Objectives: The student should be able to: 1) Identify and name major bones, and bone structures, in the human body. 2) Compare bone sizes and be able to estimate the gender and size of the person. 3) Make accurate measurements and calculate proportions for appropriate size ranges of other bones in the same person. Activities: 1) Identify the bone by comparing its shape to known samples from the intact skeleton. 2) Make measurements of length and girth of each of the bones. 3) Determine approximate size of the person by proportions of bone lengths. 4) Determine the gender of the person by examination of hip (pelvic) structure. II. 2. Galton s distinctiveness of fingerprints 3. Lattes categorized ABO blood groups 4. Goddard determined if bullet fired by a particular gun B. FBI under Hoover made large-scale effort in forensics 1. Extend to state and local authorities Crime laboratory A. Basic services 1. Physical science unit a. Uses chemistry, physics and geology b. Identify drugs c. Soil and mineral analyses d. Examine trace physical evidence 2. Biological unit a. DNA analysis b. Blood and body fluid identification c. Comparison of hairs and fibers d. Botanical comparisons

2 3. Firearms unit a. Examine guns, previously-fired bullets, cartridge cases, shells and ammunition b. Clothes and objects examined to determine type of gun and position of shooter 4. Photography unit a. Examines and records physical evidence b. Digital imaging c. Infrared, X-ray, ultraviolet photography d. Create exhibits for courtrooms B. Full-service 1. Toxicology unit a. Study body fluids and organs to determine presence or absenc e of drugs i. Ex. Blood-alcohol b. Lat ent fingerprinting i. Hidden fingerprint analyses c. Polygraph unit d. Voiceprint analyses i. Use sound spectrograph to identify voices e. Evidence-collection unit i. Protect and preserve evidence from crime scene C. Other forensic services 1. Forensic pathology a. Investigation of sudden, violent or unexplained deaths b. Usually a coroner c. Questions sought to answer: i. Who is victim ii. What injuries are present iii. When did the injuries occur iv. Why and how were the injuries produced d. Autopsy to establish cause of death e. Classification of deaths i. Natural ii. Homicide iii. Suicide iv. Accident v. Undetermined f. Estimating time of death i. Rigor mortis Within 24 hours but gone after 36 hours Muscles become rigid ii. Livor mortis Settling of blood to parts closest to ground Can be used to see if body has been moved iii. Algor mortis

3 III. IV. Body temperature cools 1 to 1 1 / 0 2 F per hour iv. Potassium levels in ocular fluid Cells within eye release Potassium after death 2. Forensic anthropology a. Examination of human skeletal remains b. Determine age, approximate age, sex, race, skeletal injury 3. Forensic entomology a. Can be used to estimate time of death 4. Forensic psychiatry a. Human behavior and legal proceedings are examined b. See if people are competent to stand trial or make a will c. Develop profiles of criminals 5. Forensic engineering a. Fires, explosions, structural failures, accidents Court cases involving use of forensics in judicial proceedings A. Frye v. United States 1. Decision of admission of procedures, techniques and principles depends on its general acceptance by a meaningful segment of the scientific community B. Daubert v. Merrell Dow Pharmaceutical, Inc 1. Frye standard not absolute and evidence can be admitted even if not general acceptance by a meaningful segment of the scientific community 2. Made trial judges responsible for determining acceptance a. Guidelines i. Scientific technique or theory can be tested ii. If it has been subject to peer review iii. Its potential rate of error iv. Standards controlling the technique s operation v. Widespread acceptance in scientific community b. Allows for admission of new techniques unique to solving new problems Processing the crime scene A. Physical evidence 1. All objects that a crime has been committed 2. All objects that provide link between crime and victim 3. All objects that provide link between crime and its perpetrator B. Securing crime scene 1. First officer that arrives must secure scene 2. Lead investigator will develop plan to document scene C. Photograph evidence while it is unaltered 1. If objec ts moved then pictures may not be admitted as evidence a. If moved must be noted in report 2. Pictures of entire scene including points of exit and entry

4 3. Surrounding areas where important events occurred before or after crime 4. If indoors all wall areas photographed and adjacent rooms 5. If body then photos of body position and location relative to entire scene a. Close-ups to show injuries and weapons b. Surface beneath body after it has been removed 6. Each item at scene is photographed to show position relative to entire scene a. Then close-ups to show details of itself b. Include ruler or something to show size 7. Videotaping where one records and one narrates as go through area 8. Note: photography shows detail better than video D. Sketches 1. Rough sketch shows dimensions of scene and location of all objects a. Create a legend b. Objects are located by two fixed points like walls c. Compass pointing north 2. Finished sketch is prepared with craftsman s tools E. Notes 1. Detailed description of scene with location of physical evidence found 2. Must be detailed because coming back to it in months or years 3. Record time evidence found and by whom a. Also need who and how it was packed and marked by 4. Tape recording can also be useful 5. Video allows for photo and notes at once but must be transcribed eventually

5 CRIME SCENE PROCESSING SCALED DIAGRAMS BACKGROUND: Students have learned about securing a crime scene, search patterns in a crime scene, and appropriate chains of custody for collected evidence. PROCEDURE: A mock crime scene is set up by the instructor at lab tables. The scene should include several objects (evidence) around the table. The students are to measure the perimeter of the table, make measurements to each of the objects from the perimeter, and make a scaled diagram of this crime scene. Optional Extension: A more realistic mock crime scene can be set up outside, where students must make larger measurements to make their scaled diagrams. They must also use one of the search patterns discussed in class when processing a larger crime scene outside. EXPECTED OUTCOMES: Students will be able to make accurate measurements, and transfer these measurements onto a true-scaled diagram. F. Systematic searches 1. Need to be done so that no accusations of cover up arise or overlook of evidence is incompetence 2. Need one person in control to coordinate collection of evidence in searches 3. Spiral, line, grid or quadrant searches may be employed 4. Many items are microscopic or undetectable at scene a. Ex. Hair, blood, fibers from clothes b. May need a broom or special vacuum to use under the microscope 5. Collecting clothing of suspect should be dome 6. Scraping under finger nail with toothpick of suspect 7. Victim s autopsy: material sent to lab a. Clothing b. Fingernail scrapings c. Hairs d. Blood e. Vaginal, anal, oral swabs for sex linked crimes f. Bullets from body G. Collecting and packaging evidence 1. Purpose is to prevent any changes between time it was removed and time received at lab

6 2. Nothing should be tampered with until it reaches lab a. Ex. Not pulling hair off of clothes 3. Pill bottles are good for storing small objects 4. Manila envelopes are also good 5. Clothes must be air dried and stored individually in a paper bag a. Stops mold and mildew from ruining evidence H. Maintain chain of custody 1. Scene, transport, lab 2. Sign out if removed I. Controls 1. Hair at scene and hair from suspect J. Crime scene safety 1. AIDS and hepatitis B from body fluids 2. Officers with contact must have had a hepatitis vaccination K. Legality 1. Can t search unless a probable cause 2. Exceptions: a. Emergency situation b. Need to prevent immediate loss of evidence c. If made with a lawful arrest d. Consent of all parties V. Physical evidence A. Types of physical evidence 1. Blood, semen, saliva 2. Documents 3. Drugs 4. Explosives 5. Fibers 6. Fingerprints 7. Firearms and ammunition 8. Glass 9. Impressions 10. Organs and physiological fluids 11. Paint 12. Petroleum products 13. Plastic bags 14. Plastic, rubber 15. Powder residues 16. Serial numbers 17. Soil and minerals 18. Tool marks 19. Vehicle lights 20. Wood and other vegetative matter B. Identification 1. Determine what type of chemical or substance 2. Ex. Type of drugs, explosives, or species of a hair

7 VI. 3. Steps involved a. Design systematic analysis that will always test for that substance b. Testing must eliminate all other possibilities c. Some substances require 1 to 10 tests C. Comparison 1. Attempts to establish if two or more objects have a common origin 2. Select properties from suspect and control specimens 3. Give conclusions as probability 4. Two types of characteristics a. Individual characteristics are substances that are related at almost 100% probability i. Fingerprints are 1 X that two people are same b. Class characteristics i. Substance can be associated with a group but not individual source Ex. Blood types 1. Can use additional factors in blood At crime scene, a lot of these can identify suspect D. Crime scene reconstruction 1. Outline of a likely sequence of events 2. Done by physical evidence, observations and statements a. Need medical examiners, forensic scientists and officers 3. Steps to reconstruct a. Secure scene b. Preliminary examination of scene i. Develop hypothesis using naked eye to piece events together ii. Develop attack plan to search the crime scene c. Go through scene for physical evidence Physical versus chemical properties A. Physical describes substance without reference to other substances 1. Ex. Mass, density, color B. Chemical describes behavior of substance when it reacts or combines with another substance 1. Ex. Wood burning, Marquis reagent and heroin C. Properties are usually related to metric system 1. 1 Liter = 1,000 cubic centimeters (cc) a. Or 1 ml = 1cc 2. Metric to English conversions, vice versa D. Physical properties 1. Temperature a. Melting, boiling, freezing points b. 0 F, 0 C, O K 2. Weight and mass

8 a. Weight versus mass b. W = mg 3. Density a. D = M/V i. Independent of size of material b. Methods to measure volume c. Must note temperature of gas and liquid because density changes with temperature i. Solid more dense than liquid than gas Density Objectives: The student should be able to: 1) Explain what is mean by density. 2) Evaluate how atmospheric conditions can alter the density of an object. 3) Determine the volume of an object using multiple methods. 4) Calculate density mathematically. D= M / V Activities: 1) The student will calculate the volume regularly shaped objects using three different methods: a. Measure length * width * height b. Perform volume displacement using only the graduated cylinder. c. Perform volume displacement using the overflow cans. 2) Calculate the density using each volume for each object. 3) Find percent error between the most (measuring) and least (overflow can, and volume displacement) methods VII. Physical properties of glass A. Refractive index 1. Light slows when it hits another medium 2. Decrease in speed causes light to bend (refraction) a. Ex. Object at bottom of pool 3. Refraction index is ratio of speed of light in vacuum to its speed in another medium 4. Refractive index = velocity of light in vacuum/ velocity in medium a. Water at 25 0 C index = times faster in vacuum i. Means times faster in vacuum 5. Dependent on temperature and the frequency of the wavelength of light a. Use standard wavelength called the sodium D light 6. Transparent solid will disappear if placed in a liquid with similar refractive index

9 7. Amorphous solids have atoms arranged randomly so have one refractive index 8. Crystalline solids have atoms arranged in orderly manner so have two indexes a. Known as double refraction b. Calcite can be placed on writing and see two of each letter i. One index is and other is ii. Difference is known as birefringence Birefringence is.172 Used to classify crystals 9. Dispersion is process of separating light into its colors (wavelengths) a. Prism B. Comparing glass fragments 1. Can be used to place a suspect at the crime scene 2. Structure of glass a. Amorphous solid b. Composed of silicon oxides mixed with various metal oxides i. Glass made when sand is mixed with metal oxides and melted and cooled Soda added to lower sands melting point and viscosity Lime is added so the glass will not dissolve in water Soda-lime glass Addition of metal oxides such as sodium, calcium, magnesium and aluminum c. Borosilicates use Boron oxide to make glass such as Pyrex d. Tempered glass made by adding stress from rapid heating and cooling i. It breaks instead of shatters ii. Used in cars e. Laminated glass contains a piece of plastic between two pieces of ordinary glass 3. Matching glass fragments a. Suspect and crime scene fragments fit together means statistically impossible not to be from same source b. Much of glass is usually to fragmented to match 4. Density and refractive index are best properties to examine a. These properties are class characteristics b. Density can be measured by using the flotation method i. Control glass added to liquid ii. Density of liquid adjusted until control glass suspended iii. Unknown is then added to see if it floats or sinks

10 c. Refractive index determined by immersion method i. Glass put into liquid ii. Refractive index of liquid adjusted by temperature until a match point is reached Point when Becke line disappears because both liquid and glass have same refractive index iii. Hot stage or GRIM 2 used 5. If density and refractive values different from suspect and scene than not from same source 6. If same still can t identify it from one source a. Must compare results with frequency of occurrence of glass in society i. Scientist can make a meaningful assessment as to probability that the fragments were at one time from one source 7. Tempered versus non-tempered glass a. Determined by process called annealing i. Involves slowly heating then cooling glass ii. Change in refractive index for tempered is much greater than non-tempered Refractive indexes Objectives: The student should be able to: 1) Explain what is meant by refractive index. 2) Observe and compare refractive indexes of knowns and unknowns in lab. 3) Predict what causes the difference in refractive indexes in each of the samples. 4) Recognize the cause of refractive indexes and its effect on different crime scenes. Activities: 1) Mount a piece of glass in the first trial (sodium chloride crystal in the second trial) to the microscope slide. 2) Add a drop of the liquid to the top of the glass particle. Record the distances of the Becke Line (halo) for each substance. Measure if using a ruler in mm. Focus in and out of the plane of the liquid to best see the Becke Line. C. Glass fractures 1. Glass bends when force exerted 2. If force greater than glass s elasticity, it fractures 3. Penetration of glass leaves typical fracture patterns a. Radial fractures

11 VIII. b. Concentric fractures 4. Size and shape of hole can t be sole factor of projectile a. Ex. Small stone throw hard enough leaves similar hole as bullet b. Large stone shatters window just like a gun at close range i. Gun powder left behind id it is a gun c. Hole from projectile can determine direction it came from i. Hole is wider at exit side d. As velocity of bullet decreases the irregularity of shape and surrounding cracks increase 5. Formation of radial lines a. Form on opposite side of penetrating force b. SEE TOM D. Collection and preservation of glass evidence 1. All glass must be found to increase odds of matching pieces together from suspect and crime scene 2. Must submit all glass samples found on suspect and a sample of broken glass (control glass) from crime scene a. Control glass should be taken from area closest to point of breakage b. Glass should be placed in solid containers to avoid further breakage c. Individually wrap each garment from suspect. Glass should not be removed from these Physical properties of soil A. Soil characteristics 1. Any natural or unnatural item found on or near Earth s surface a. Ex. Rocks, minerals, vegetation, glass, paint chips, etc 2. Can link suspect to crime scene based on its transferability 3. Comparison of soil can begin with simple observation a. Color can be used only if samples are dry b. Microscopes allow to see plant and animal remains 4. Minerals can be identified along with their concentrations a. Mineral is a naturally occurring crystal with definitive physical properties 5. Rocks and minerals used as building materials so can compare these pieces also 6. Density-gradient tube is used to determine density distribution of soil a. Clear tube is filled with liquids of various densities 7. Soil texture can be used to determine type of soil B. Collecting and preserving soil evidence 1. Samples taken at crime scene and at intervals within a 100 yard radius a. Establishes variation of soil at scene 2. Samples should also be collected at all of suspect s alibi places

12 IX. 3. These samples should only include top soil layer because it is only part transported 4. Should be packed in plastic vials and marked to location 5. Garments with soil should be individually wrapped in paper bags 6. Clumps of soil should not be broken up Analysis of organic compounds A. Matter is anything that has mass and occupies space B. Element is simplest substance that provides building blocks that compose matter 1. Smallest particle of element and has its property is the atom C. Compound is two elements joined 1. Molecule is smallest unit of a compound a. Ex. one molecule of the compound CO 2 D. Physical states of matter 1. Relationship to volume and shape 2. Conversion into various states a. Sublimation E. Organic versus inorganic F. Selecting analytical technique 1. First if organic or inorganic 2. Qualitative versus quantitative determination a. Former seeks to identify material only b. Second seeks to find % combination of components of mixture G. Chromatography is separation and analyses of mixtures of chemical substances 1. Occurs due to the observation that substances partially escape into environment when dissolved in a liquid or when absorbed on a solid surface 2. Dissolved gas molecules in a liquid will leave and reenter liquid into equilibrium is reached. a. The higher the solubility of gas in liquid, the more molecules that stay in solution 3. Requires a stationary phase and moving phase in contact with one another a. If moving air is in contact with stationary water, then gas out of liquid will be pushed along b. Gas with high solubility will take longer to move i. Allows for identification based on retention time H. Gas chromatography (GC) 1. Separates mixtures based on a stationary liquid phase and a moving gas phase 2. Works well on highly complex mixtures 3. Allow for identification and quantification of each compound 4. Design of procedure a. Carrier gas moves through column at a constant rate

13 i. Gas must be inert so it does not react with mixture b. Mixture injected as liquid into heated port to vaporize it c. This vaporized material is swept through column by carrier gas i. Column is filled with a liquid d. Column is continuously heated to keep it as a gas e. Substances in mixture with high affinity for liquid phase will be slow, vice versa f. Long column allows for a complete separation of mixture g. Each component enters a detector as it emerged from column i. Records its retention time on a chromatogram ii. Compared to a standard to determine type 5. Pyrolysis gas chromatography is used for substances that can t be directly injected into GC chamber a. These materials are heated to high temperature so they decompose into numerous gaseous products b. Then the gas is injected into column I. High-performance liquid chromatography (HPLC) 1. Advantage is that it can be done at room temperature 2. Moving phase is liquid and stationary is fine solid particles 3. Liquid carries unknown mixture over particles 4. Substances are slowed as it interacts with particles a. Allows for identification based on retention time J. Thin-layer chromatography (TLC) 1. Solid stationary phase and a liquid moving phase 2. Sample must be a liquid or solid dissolved in a liquid 3. Liquid moves up column picking up unknown mixture 4. Compounds that have high affinity for solid do not move as far 5. The paper is removed and allowed to dry 6. Finding the various compounds requires fluorescence a. Need an ultraviolet light 7. Finding can also be done by spraying chemical on paper to cause compounds to generate colored spots 8. Identification of compounds is then done by comparing it to known sample

14 QUESTIONED DOCUMENTS TLC BACKGROUND: Students have learned about various methods of analysis, including chromatography. Since expense prohibits high schools from actually performing chromatographic analysis, this lab is intended to show the basics behind such testing. PROCEDURE: Students are provided with various water-based markers and filter paper. They are to observe and measure how a solvent (water) separates the marker ink into various components, and relate their findings to chromatographic analysis in the real world. EXPECTED OUTCOMES: Students will perform an activity, which is analogous to chromatography in Forensics Laboratories, and they will increase their skills of measurement and graphing. K. Electrophoresis 1. Separates protein and DNA based on their sizes and charges 2. Done by placing samples into wells of a solid gel 3. Opposite charges at each side cause sample to move L. Properties of light 1. Electromagnetic spectrum components can be distinguished by wavelengths or frequencies 2. Objects have color due to absorption and reflection of various wavelengths of light 3. Light acts as a wave a. Wave can be measured by wavelengths (trough to trough) b. Measured by frequency (number of crests passing given point in a set time) 4. Light acts as a photon a. Higher frequency means more energy b. More energy means more dangerous for humans M. Spectrophotometry 1. Measures the amount of radiation a material absorbs 2. Dependent on frequency or wavelength of radiation 3. Material can be quantified because the more material the more radiation it will absorb 4. Spectrophotometer a. Graphs results in form called absorption spectrum b. Radiation source

15 c. Monochromator selects single wavelength d. Holder for sample e. Detector measures unabsorbed radiation f. Graph to make absorption spectrum g. Use of UV as radiation source produces an absorption spectrum that usually can t ultimately distinguish it h. Use of infrared produces a complex pattern that can be used as a chemical s fingerprint N. Mass spectrometry 1. Coupled with GC to specifically identify a substance 2. Each gas component coming from GC passes into spectrometer 3. Inside it is collided with electrons 4. The collision causes materials to lose electrons and ultimately become unstable 5. This leads to molecular break down 6. Each of these smaller fragments can be separated by mass by going through a magnetic field 7. No two substances produce same fragmentation pattern X. Analysis of inorganic compounds A. Inorganic analyses is used to identify explosives, paints, metals, etc B. Analyses can identify if two or more objects come from a similar source 1. Manufactured goods require raw materials from Earth s crust 2. Crust contains various trace elements or impurities at certain locations C. Emission spectrum of elements 1. Elements can absorb and emit wavelengths of light 2. Allow for emission spectroscopy and atomic absorption spectrophotometry 3. Emission spectrum is the light emitted from a source and is separated into its colors or frequencies a. Light from sun or incandescent bulb has an emission spectrum that is continuous b. Elements produce discontinuous or line spectrum that is distinctive for that element i. Must be a gas that is excited by high temperature c. Emission spectrograph obtains and records line spectra of elements i. Needs means for vaporizing elements to emit light Done by direct electric currents ii. Component to separate this light Can be done by a prism iii. Means to record separation d. Substances usually contain more than one element so must match graph to known patterns of elements e. Used to identify mutilated bullets, paint chips and glass pieces

16 4. Atomic absorption spectrophotometry a. Based on principle that elements will absorb same frequencies as it emits when vaporized b. Specimen is heated to cause it to vaporize c. Specimen is then exposed to radiation source i. Best if radiation source is made of a discharge tube of same element one is trying to identify ii. Means light only absorbed if sample contains that element d. A detector sends information to graphing station e. Can detect elements at levels as small as one-trillionth of a gram D. Origin of emission and absorption spectra 1. Based on energy levels of electrons 2. Each element has a specific arrangement of electrons in energy levels 3. Ground state versus excited state 4. To move electrons to different levels requires absorption or release of specific amounts of energy a. Thus absorb specific frequency of light and release same frequency 5. Any other amount of energy will have no effect E. Neutron activation analyses 1. Based on principles of isotopes and radiation 2. Some isotopes undergo radioactive decay a. Alpha rays are positively charged particles b. Beta rays are electrons being emitted c. Gamma rays is a type of powerful electromagnetic radiation 3. Neutron activation analysis bombards material with neutrons a. The elements in substance will absorb some and immediately decompose releasing radioactivity b. Each element has a characteristic energy value given off as gamma ray radiation c. Concentration can be measured by intensity of it gamma ray radiation i. Direct relationship d. Identifies trace elements in drugs, poisons, metals, soils, etc F. X-ray diffraction 1. Used to identify how elements are combined into molecules 2. Works on crystalline solids a. Most of inorganic material is this type 3. X-rays are sent into compound which is reflected off of the atomic planes of substance 4. These diffraction patterns are then recorded on photographic film

17 XI. XII. 5. Every compound has its own diffraction pattern Microscopes in forensics A. Compound light microscope 1. Mechanical structure supports apparatus 2. Optical system a. Object is reversed b. Transmitted versus reflected illumination c. Condenser focuses light on specimen d. Objectives e. Monocular versus binocular f. Total magnification g. Resolution limits magnification to no more than 1,000X h. Field of view i. Depth of focus B. Comparison microscope 1. Two compound joined by lenses to one binocular unit 2. Allows for side-by-side comparisons C. Stereoscopic microscope 1. Allows for three dimensional viewing of object 2. Has low magnification 3. Image is not reversed D. Microspectrophotometer 1. Combines microscope and spectrophotometer 2. Shines various light wavelengths onto specimen during observation a. Allows for determination of absorption spectrum E. Electron microscope 1. Allows for high magnification and depth of focus 2. Beams a wave of electrons onto specimen a. Causes other electrons to be emitted from elements on surface of specimen 3. Can be used with X-ray analyzer to determine distribution of elements in specimen Physical properties of hair A. Morphology of hair 1. Class characteristic because not individual specific 2. Can be used as strong corroborative evidence 3. Structure a. Grows from hair follicle b. Hair made up of cuticle, cortex and medulla c. Cuticle i. Gives hair resistance to chemical breakdown and retains its structural features Results in important forensic use ii. Overlapping scales always point towards tip end of hair

18 iii. Scale pattern allows for differentiation of species iv. Study scale by SEM or embedding into soft medium Ex. nail polish or softened vinyl Remove after medium has hardened and view under microscope d. Cortex is main part of hair i. Important because it has pigment granules Compare color, shape and distribution ii. Examine by mounting in a liquid with similar refractive index Allows for less light to be reflected and light penetrating is optimized e. Medulla is cellular column running through middle of hair i. Medullary index is how much of diameter of hair the medulla takes up Humans is less than 1/3, animals more than ½ ii. Medulla can vary even in same individual iii. Shape of medulla is also important Humans and most animals have cylindrical shape f. Root produces hair and keep it going i. Hair growth occurs in three phases Determine shape and size of root Anagen has hair attached to follicle for continued growth 1. Flame-shaped 2. If this hair pulled usually has a piece of tissue attached a. DNA analysis can individualize Catagen has slight continued growth 1. Elongated appearance Telogen is when growth phase ends 1. Club shaped 2. Hair will eventually pushed out causing shedding B. Identification and comparison of hair 1. Comparison done to see if human hair and to match with suspect a. Difficult because structural features different even with same individual i. Need many samples from scene and individual 2. Important characteristics include color, intensity of pigment granules, length, diameter, scale structure, medullary index and shape of medullae 3. Comparison microscope should be used

19 4. Can identify dyed and bleached hair a. Roots will be natural color if hair growth after dying b. Can also identify time since dying i. Hair grows 1 cm per month 5. Examiners can usually determine part of body part hair came from a. See book for details 6. May be able to determine racial origin of hair 7. If hair has root tissues still attached can do DNA analysis to specifically identify individual a. Uses nuclear DNA 8. Currently working on extracting DNA from hair in anagen phase 9. Mitochondrial DNA currently being examined a. Only passed on from mother to child b. Many copies in each cell C. Collection of hair evidence 1. Need many samples from scene and suspect; about Hairs must come from same area of body Hair analysis Objectives: The student should be able to: 1) Demonstrate the proper use of a microscope. 2) Use the proper techniques for preparing mounted slides of hair samples. 3) Compare the different hair samples. 4) Classify the hair samples into groups. 5) Predict the suspected source of the hair sample Activities: 1) Review use of the microscope and procedure for preparing mounted slides. 2) Obtain 4 different unknown hair samples. 3) Prepare and examine each slide of the samples; note color, texture, condition. 4) Observe the shaft and root of each sample. 5) Make a sketch of all the samples, highlighting the unique properties of each. XIII. Physical characteristics of fibers 1. Class characteristic because of mass use of fibers 2. Natura l fibers are generated from natural animal and plant sources a. Identification and comparison based on color and structural characteristics b. Cot ton is most common i. Microscopic view shows ribbon like shape with

20 twists at irregular intervals 3. Man made fibers a. Ex Rayon and Nylon b. Regenerated fibers have parts made from wood or cotton c. Synthetic fibers made solely from chemical polymers i. Polymers are long-chained molecules created from condensation synthesis of monomers ii. Starch versus cellulose B. Identification and comparison of man made fibers 1. Compare color and diameter of control and crime scene specimens 2. Compare lengthwise striations on surface of some fibers 3. Fibers can be broken down into more than two dozen subclasses 4. Dyes in fibers allow for a good comparison of specimens a. Leads to a more individualistic identification b. Done by Microspectrophotometer c. Can use a chromatographic spectrum to separate dyes 5. Fibers demonstrate a double refraction because its coating polymer forms a crystalline solid a. Each subclass of fibers has specific index of refraction 6. Infrared spectrophotometry can be used because of organic matter in fibe r a. Selectively absorbs infrared radiation based on each subclass of fibers 7. Thousands of colors, shape and microscopic appearance can really serve to narrow down fiber differences C. Collection of fiber evidence 1. Difficult because usually not visible to naked eye 2. Necessary to identify potential carriers of fibers 3. Clothing should be wrapped in paper bags 4. Fold rugs and linen to ensure fibers will not fall off 5. Use tweezers if you find it necessary to pick up a fiber XIV. Physical properties of paint A. Forensic examination of paint 1. Piece of paint can determine make, model, color and year of car 2. Paint is made of pigments, additives held together by a binder 3. Auto paint has a variety of coatings which enhances its identification a. Electrostatic primer is first applied to stop corrosion b. Prim er surface added to hide imperfections i. Highly pigmented c. Base coat is the color one sees on a car d. Clear coat is non-pigmented to improve appearance and durability e. Evaluation of layered structure can narrow identification but still a class characteristic 4. Various binder formulations in paint

21 XV. 5. Finishes are found in hundreds of varieties 6. Analyses a. Gas chromatography creates specific programs b. Infrared spectrophotometry to distinguish binders B. Collection of paint evidence 1. Try to keep paint chip intact 2. Paint should not be touched by uncovered hands 3. If chip is embedded in material than it all should be packaged together 4. Collection of control should e done on an undamaged part C. Damaged part can show corrosion, new paint or fading Physical evidence of drugs A. Drug is any substance that causes a physiological or a psychological affect B. Drug dependency 1. Psychological dependence a. Drugs create sense of well being or escape i. Narcotics, steroids b. Can manifest into desire to avoid withdrawal sickness 2. Physical dependency a. Occur s from regular schedule of drug intake i. Drug effect does not have time to wear off b. Marijuana, LSD, cocaine not proven to have physical dependency 3. Social impact C. Narcotic drugs 1. Misused to represent all illegal drugs 2. Painkiller that depresses vital body functions 3. Source of lost is from opium a. From unripe pod of a poppy plant b. Morphine is extract of opium c. Heroine is derivative of morphine i. Solubility allows for injection for immediate affect ii. 35% of drug is heroin; 65% is other material Could be quinine, starch D. Hallucinogens 1. Cause alteration in normal thought process 2. Marijuana is an example a. Comes from cannabis plant b. Consists of mixed leaves with parts of plant s flower, stem, seeds c. THC is chemical that gives its property 3. LSD is derived from fungus a. Creates vivid hallucinations b. User can be prone to flashbacks 4. PCP (angel dust) a. Intake begins with feeling of strength and invulnerability

22 b. Followed by depression and tendency to violence 5. Ecstasy a. Enhances awareness and decreases inhibitions E. Depressants 1. Alcohol works on CNS a. Affects memory, reaction time and concentration 2. Barbiturates (downers) a. Also act on CNS b. Causes relaxation and sleepiness c. Taken orally and is dangerous if overused 3. Tranquilizers are depressants that don t affect high order thinking skills F. Glue sniffers 1. Immediate feeling of euphoria 2. Have slurred speech, double vision, impaired judgment 3. Affects CNS as a depressant 4. Danger of affecting liver, heart and brain and can cause death G. Amphetamines (uppers) 1. Initial increase in alertness followed by fatigue and appetite loss 2. Causes restlessness, apprehension and depression after it wears off 3. Taken orally or intravenously 4. Strong psychological dependency H. Cocaine 1. From coca plant 2. Powerful stimulant to CNS 3. Increases alertness and vigor 4. Sniffed through nose 5. Crack is derivative of cocaine a. Can be smoked to get affect quicker b. Extremely addictive 6. Both creates euphoria by stimulating pleasure center in brain 7. Euphoria leaves quickly leaving severe depression I. Anabolic steroids 1. Related to male sex hormone testosterone a. Promotes secondary sex characteristics b. Accelerates muscle growth 2. Negative effects on liver specifically a. Infertility, lower sex drive, stops bone growth b. Produces severe mood swings J. Drug control laws 1. Medical and legal definitions of drugs differ 2. Penalties dependent on amount or percent of drug a. Important for scientist to distinguish these factors K. Drug identification 1. Screening tests done first to eliminate 1000 s of substances a. Put material to color tests

23 i. Marquis Reagent turns purple for heroin, morphine Orange-brown for amphetamines ii. Dille-Koppanyi turns violet-blue for barbiturates iii. Duquenois-Levine turns purple for marijuana Must also be paired with a microscope analysis 1. Leaves have hair in shape of bear claws iv. Van Urk turns blue-purple for LSD v. Scott Test turns blue for cocaine 2. Second phase pinpoints exact substance a. Done by a confirmation test i. Any single test that can identify a substance 3. Microcrystalline tests a. Chemical added to drug causes formation of crystals that can seen with microscope b. Drugs have specific crystal patterns and sizes c. More specific than color tests d. Do not have to separate drug from diluents 4. Chromatography can be used to identify drugs a. TLC and gas chromatography are best b. Can be made more useful if used with mass spectrometry 5. Spectrophotometry a. Infrared is one of a few tests to specifically identify drug b. Requires the substance to be pure so many preliminary steps L. Collection and preservation of drug evidence 1. Does not require major complications 2. Make sure packaged and labeled properly 3. Place volatile solvents into air tight bag 4. Helpful to scientist if investigator can give background information related to drug s identity XVI. Forensic toxicology A. Forensic toxicology is to detect and isolate drugs in body to determine their affects on the body and behavior B. Effects of alcohol 1. Affect CNS 2. First affect nerve functions in forebrain 3. Increase consumption affects nerves in central and rear portions C. Alcohol in body 1. Moves into bloodstream via stomach and small intestines 2. Becomes distributed uniformly in watery portions of body a. If no blood in dead body, can still test 3. Body rids by: a. Oxidation into carbon dioxide and water in liver i. Enzyme is alcohol dehydrogenase

24 b. Excreti on occurs through breath, urine, sweat i. Here the alcohol is unchanged 4. Concentration in body can be determined by: a. Direct chemical analysis of blood b. Measuring content of breath and relating to blood-alcohol concentration i. Determined by Henry s Law ii. Fixed ratio of volatile compound in air and its concentration in liquid D. Breath-test instruments 1. Design a. Breathing into mouthpiece sends air to an ampoule b. Alcohol causes chemicals to react ultimately destroying potassium dichromate i. More alcohol less potassium dichromate c. This means it cannot absorb as much light d. More light passing through, the more alcohol e. Works like a spectrophotometer f. Standard ampoule used to zero scale g. Fuel cell tests alcohol by oxidizing the alcohol in one s breath i. Creates a current proportional to amount of alcohol in body E. Field sobriety tests include a series of psychophysical tests 1. One-leg stand, alphabet, etc F. Collection and preservation of blood 1. Must antiseptically carried out blood withdrawal a. Prevents claims of contamination of sample 2. Anticoagulant added to prevent clotting 3. Preservative added to decrease growth of microorganisms 4. Blood stored in refrigerator 5. All prevents decline in alcohol concentrations in blood 6. Collection of blood in dead body requires several samples over entire body a. Due to formation of ethyl alcohol production from bacteria G. Role of toxicologist 1. Must identify toxins and drugs from a small sample of blood 2. Difficult because concentrations much smaller than found in pills or powders 3. Difficult because body metabolizes material to form metabolites a. Heroin quickly changed to morphine b. Morphine binds to carbohydrates before excretion 4. Helpful if connection to victim s symptoms or method of death 5. Need input from investigator, medical examiner and physician 6. Dead body allows medical examiner to decide which biological samples to send to lab

25 7. Living person must get samples of blood and urine H. Toxicological techniques 1. First step is to remove toxins and drugs from biological material a. Done by dissolving sample into water b. Changing its ph allows for extraction of various toxins/drugs 2. Screening done to see if specimen contains a drug a. Allows for examination of large number of specimens for a wide variety of tests b. Can use TLC, gas chromatography (GC), immunoassay i. Immunoassay dependent on specific antibody reaction to drugs ii. Allows for detection of very small drug concentrations 3. Confirmation test fortifies screening test a. Use GC and mass spectrophotometry 4. Hea vy metals (arsenic, lead) can be identified a. Dissolve body fluid or tissue in HCl b. If a copper strip is added and turns silvery, heavy metals present c. Confirm and identify specific type by absorption spectrophotometry 5. Carbon monoxide combines with hemoglobin preventing oxygen from being carried to body a. Concentration in blood done by: i. Spectrophotometers ii. Blood can be treated to release CO Then measured by gas chromatography I. Need to determine how drug concentration will affect an individual 1. Depends on sex, age, past use 2. Two or more drugs may have synergistic affects XVII. Arson and explosions A. Chemistry of fire 1. Oxidation is the addition of oxygen to a substance a. Methane consumption reaction b. Necessary for fire or explosion 2. Combustion will not occur unless activation energy is reached a. Usually accomplished through sufficient heat b. Lit match and gasoline has enough c. Oxygen and methane alone does not 3. Production of fire occurs only when material is in gas phase a. Wood will not combust until enough heat to decompose solid into vapor i. Pyrolysis is chemical breakdown of solid b. Flashpoint is lowest temperature in which substance gives off enough vapor to support combustion

26 c. Still requires a much higher temperature to start combustion 4. Heat of combustion reaction is usually sufficient to keep it going 5. Spontaneous combustion is fire that is caused by natural heat source a. Bacteria living on hay can generate enough heat 6. Explosives undergo rapid exergonic reactions that produce large quantities of gas a. Requires oxidizing agent other than oxygen because it can t get to gas fast enough to produce explosion B. Most arson fires started with accelerants 1. Petroleum-based 2. Gasoline or kerosene are examples 3. Evaporate quickly after fire so must investigate scene quickly C. Primary focus of search is to find origin of fire 1. May find multiple separate fires 2. May find streamers used to spread the fire a. Ex. Trail of gasoline 3. Also important to look for signs of breaking and entering and theft 4. Since fire moves upward, origin likely at lowest point with intense characteristics of burning 5. Flammable liquids flow to lowest point so more severe burning on floor may mean an accelerant 6. More burning at bottom of furniture than top may also mean accelerant 7. Look for accelerant in porous material 8. Vapor detector can screen material for presence of accelerant D. Collection and preservation of arson evidence 1. Need 2-3 quarts of ash near point of origin 2. Collection of evidence should include all porous materials thought to have flammable residues 3. Material must be packaged in airtight containers to stop evaporation 4. Need substrate control for each specimen collected a. Sample of similar but uncontaminated specimen b. Done to ensure an arson accelerant used c. Ex. Fire set by accidental use of a rug cleaner on a carpet. 5. Search for igniters like matches a. Force of habit could cause one to blow out match and toss away 6. Clothing of suspect may still have accelerants 7. Freeze soil and plant samples believed to have accelerant a. Bacteria can decompose it E. Arson analytical techniques 1. GC is very important instrument 2. Typical accelerants are gasoline and kerosene

27 a. Made of lots of hydrocarbons 3. GC separates hydrocarbons to identify specific accelerant 4. Headspace technique involves heating airtight container with sample a. Syringe used to extract vaporized volatile and put into GC 5. Vapor concentration technique places charcoal strip in container a. Container heated so charcoal can absorb accelerant vapor b. Allows for increase amount of accelerant c. Allows for increase in sensitivity for GC testing F. Explosives 1. Mostly face incidents with homemade explosives 2. Scientist must search scene for chemical remainders 3. Explosion different from fire by rate of creation of gas and heat 4. Container that has explosives can become projectile like in a pipe bomb 5. Blast effect is outward rush of gasses which can knock down objects 6. Speed of explosive deterioration varies greatly allowing for classification a. Low and high explosives b. Low explosives speed called speed of deflation c. High explosive called sped of detonation G. Low explosive 1. Rapid oxidation produces, heat, light and subsonic pressure wave 2. Slow burning rates make them good for propellants for ammo and rockets 3. Usually are only dangerous if confined 4. Most common are black powder and smokeless powder 5. Black powder made of K, charcoal and S a. Used as a safety fuse because it burns slow, allowing time to get away 6. Smokeless powder is a nitrogen based compound 7. Creation of low explosive only requires oxidizing agent and fuel a. Potassium chlorate as agent and sugar as fuel can be dangerous if confined H. High explosives 1. Extremely rapid oxidation accompanied with violent high speed shockwave that smashes and shatters 2. Show variety of sensitivities that allow for further classification a. Primary explosives are very sensitive to heat, shock or friction i. Often act as primers because used to detonate other explosives b. Secondary explosives are insensitive to heat, shock or friction i. Will burn instead of explode if not confined

28 ii. Ex. TNT I. Collection and analysis of explosives 1. Most important item is to collect samples at scene a. There is usually some undetonated material 2. Explosives leave a crater at origin of blast a. Soil and material samples from this crater 3. Material just near origin may contain fragments of explosive 4. Wire-mesh screens used to sift through remains 5. High priority to find detonating device 6. EGIS system can be used in the field to detect vapors from surfaces suspected of containing explosives 7. Microscopic examinations of undetonated material and detonating device a. Done to locate and help identify explosive 8. After microscopic examination, specimens are rinsed with acetone a. Most explosives have high solubility in acetone 9. Acetone extract then analyzed by color tests, TLC, GC and mass spectrophotometry 10. Infrared spectrophotometry can be used as a confirmatory test J. Taggant strips can be placed in some explosives K. Some survive detonation allowing investigators to better trace explosives XVIII. Forensic serology A. Serology is the study of antigen-antibody reactions B. Structure of blood 1. Plasma is mostly water and carries content of blood 2. Cells a. Erythrocytes (RBC) carry oxygen due to hemoglobin b. Leukocytes (WBC) fight off antigens c. Platelets are responsible for clotting C. Antigens on body cells 1. Present to allow one s body to recognize self 2. Responsible for conferring blood type a. A-B-O blood system i. A has A antigen on its cell ii. B has B antigen on its cell iii. AB has both iv. O has neither b. Rh blood system i. Positive blood types have a specific antigen Called D factor ii. Negative do not D. Antiserum is part of blood that carries an antigen 1. Almost every antigen has a specific antibody to destroy it 2. Antibodies attach to antigen causing agglutination E. Blood donating and receiving

29 F. Blood typing is done by adding antibodies for A, B, and D antigens on blood cells 1. Ex. agglutination of blood when antibody A is added means A antigen is present. Individual is either A or AB G. Population distribution of blood types 1. O is 43% 2. A is 42% 3. B is 12% 4. D is 3% H. Immunoassay techniques 1. Can be used for applications outside blood types 2. Can test for certain drugs and toxins by using antibodies 3. Antibodies are not found in humans so are synthesizes a. Usually inject compound with drug one is testing for into animal b. Animal makes antibodies because it is a foreign substance 4. EMIT is enzyme-multiplied immunoassay a. First add to suspects urine, antibodies to drug testing for b. Drug will then react and combine with antibody c. Second chemical added to remove any unused antibodies d. Amount of unused antibodies is measured and correlated with amount of drug present e. Often used to test or marijuana metabolites in urine I. Characterization of blood stains 1. When blood is found at crime scene must determine: a. If it is really blood b. Species of blood c. How closely it can be associated with a specific individual 2. Phenolphthalein is used to determine presence of blood a. Binds due to peroxidase-like activity of hemoglobin b. When blood, phenolphthalein and peroxide added together, a deep color will appear c. Process also called to Kastle-Meyer color test 3. Hemastix is a dipstick for blood a. Stick moistened with distilled water and dipped into sample b. Presence of blood turns stick green 4. Luminol reagent tests for blood by production of light rather than color a. Extremely sensitive and can detect minute amounts of blood b. Does not interfere with subsequent DNA analysis 5. Precipitin test determines if blood is human or animal origin a. Test chemical made by injecting animal with human blood b. Antiserum containing human antibodies created by animal are then collected