1. Forensic Science: An Introduction Unit A: Crime Scene Processing

2. Definitions Forensic Science - the application of the knowledge and technology of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system. Forensic Science - the application of the knowledge and technology of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system. Locard’s Exchange Principle – when two objects come in contact with each other, a cross-transfer of materials occur. This allows us to connect criminals to crime scenes. Locard’s Exchange Principle – when two objects come in contact with each other, a cross-transfer of materials occur. This allows us to connect criminals to crime scenes.

3. The American Academy of Forensic Science Departments Criminalistics - crime scene processing Criminalistics - crime scene processing Engineering Science - reconstruction Engineering Science - reconstruction General General Jurisprudence - legal Jurisprudence - legal Odontology - bitemarks Odontology - bitemarks Pathology/Biology – autopsy, DNA Pathology/Biology – autopsy, DNA Physical Anthropology – skeletal remains Physical Anthropology – skeletal remains Psychiatry and Behavioral Science Psychiatry and Behavioral Science Questioned Documents Questioned Documents Toxicology – drugs and poisons Toxicology – drugs and poisons

4. Additional disciplines Fingerprint examination Fingerprint examination Firearm and toolmark examination Firearm and toolmark examination Computer and digital analysis Computer and digital analysis Photography Photography Entomology - insects Entomology - insects

5. Historical Events Late 1700s - Arsenic and Toxicology Late 1700s - Arsenic and Toxicology Mid 1800s – Microscopy Mid 1800s – Microscopy Late 1800s – Identification (Bertillion) Late 1800s – Identification (Bertillion) Early 1900s – Fingerprinting, Blood and Serology, Document Examination, Microscopy Early 1900s – Fingerprinting, Blood and Serology, Document Examination, Microscopy Mid 1900s – Chromatography, Spectrophotometry, Electrophoresis, DNA Mid 1900s – Chromatography, Spectrophotometry, Electrophoresis, DNA

6. Publications Yi Yu Ji “A Collection of Criminal Cases” Yi Yu Ji “A Collection of Criminal Cases” “A Treatise on Forensic Medicine and Public Health” (Fodere, 1798) “A Treatise on Forensic Medicine and Public Health” (Fodere, 1798) “Finger Prints” (Galton, 1892) “Finger Prints” (Galton, 1892) “Criminal Investigation” (Gross, 1893) “Criminal Investigation” (Gross, 1893) Sherlock Holmes –fiction (Doyle 1880s) Sherlock Holmes –fiction (Doyle 1880s) “Treaty of Criminalistics (Locard, 1931) “Treaty of Criminalistics (Locard, 1931) Hypervariable Minisatellite Regions in Human DNA (Jeffreys, 1985) Hypervariable Minisatellite Regions in Human DNA (Jeffreys, 1985)

7. Crime Labs Locard Locard Los Angeles - oldest Los Angeles - oldest FBI FBI DEA DEA ATF ATF US Postal Service US Postal Service SBI SBI State system State system Local Local Delocalized labs – no common management Delocalized labs – no common management

8. Crime Lab Services Basic Services Photography Photography Physical Science Physical Science Biology/DNA Biology/DNA Firearms Firearms Document Examination Document Examination Optional Services Toxicology Toxicology Latent Fingerprint Latent Fingerprint Polygraphy Polygraphy Voice Analysis Voice Analysis Forensic Psychiatry Forensic Psychiatry Forensic Odontology Forensic Odontology Forensic Engineering Forensic Engineering Forensic Computer and Digital Analysis Forensic Computer and Digital Analysis

9. What Forensic Scientists Do Analyze physical evidence Analyze physical evidence Use scientific methods Use scientific methods Determine admissibility of evidence Determine admissibility of evidence Frye v US (1923) – general acceptance Frye v US (1923) – general acceptance Judge scientific evidence Judge scientific evidence Daubert case (1993) – trial judge is gatekeeper Daubert case (1993) – trial judge is gatekeeper Provide expert testimony Provide expert testimony Furnish training Furnish training

10. Forensic Science Forensic scientist seek to reach truth based on available evidence. The legal process does not, however, always seek truth but follow process. Forensic scientist seek to reach truth based on available evidence. The legal process does not, however, always seek truth but follow process. Reliable methods possess characteristics of: Reliable methods possess characteristics of: Integrity Integrity Competence Competence Defensible technique Defensible technique Relevant experience Relevant experience

11. Reliable Methods Help distinguish evidence from coincidence Help distinguish evidence from coincidence Allow alternative results to be ranked by basic scientific principles Allow alternative results to be ranked by basic scientific principles Allow tests to either prove or disprove alternative hypotheses Allow tests to either prove or disprove alternative hypotheses Pursue testing by breaking hypotheses into their smallest logical components Pursue testing by breaking hypotheses into their smallest logical components

12. Physical Evidence Anything physical objects that can link a crime to its victims or to suspects. Anything physical objects that can link a crime to its victims or to suspects. Has to be collected from crime scene Has to be collected from crime scene Must be relevant to the crime Must be relevant to the crime Requires the collector to understand what the capabilities and limitations of the crime lab are Requires the collector to understand what the capabilities and limitations of the crime lab are

13. Physical Evidence Crime labs do not solve crimes, only add evidence to help police investigation link the suspect to the crime. Crime labs do not solve crimes, only add evidence to help police investigation link the suspect to the crime. The forensic scientists must know how to collect and preserve evidence found at the crime scene The forensic scientists must know how to collect and preserve evidence found at the crime scene

14. Ways to classify a crime scene Primary vs secondary crime scene Primary vs secondary crime scene Macroscopic vs microscopic scenes Macroscopic vs microscopic scenes Type of crime Type of crime Location of crime Location of crime

15. Use of Physical Evidence Information on evidence of a crime (Corpus Delecti) Information on evidence of a crime (Corpus Delecti) Information on the criminal (Modus Operandi) Information on the criminal (Modus Operandi) Linkage on persons, scenes and objects Linkage on persons, scenes and objects Identification of suspects Identification of suspects Identification of unknown substances Identification of unknown substances Reconstruction of a crime Reconstruction of a crime Providing investigative leads Providing investigative leads

16. Arriving at the Crime Scene Secure and isolate the crime scene Secure and isolate the crime scene Determine boundaries of crime scene and priorities for evidence collection Determine boundaries of crime scene and priorities for evidence collection Rough sketch Rough sketch Finished sketch Finished sketch Photograph Photograph Videotaping Videotaping Notes Notes

17. Collecting Evidence Conduct a systematic search for evidence; be unabiased and thorough. Conduct a systematic search for evidence; be unabiased and thorough. Field technicians Field technicians What to look for depends on the crime and what specific locations of the crime scene would most likely be affected What to look for depends on the crime and what specific locations of the crime scene would most likely be affected Microscopic or massive objects Microscopic or massive objects Collect carriers of possible evidence Collect carriers of possible evidence Vacuum or sweeping collected Vacuum or sweeping collected

18. Packaging of Evidence Prevent any changes from occurring (contamination, breakage, evaporation, bending, loss) Prevent any changes from occurring (contamination, breakage, evaporation, bending, loss) Process trace evidence from original object (shirt, shoe) rather than isolating and packaging if possible Process trace evidence from original object (shirt, shoe) rather than isolating and packaging if possible Package evidence separately Package evidence separately

19. Tools for Collecting Evidence Forceps Forceps Evidence envelopes and pill bottles Evidence envelopes and pill bottles Swabs Swabs Special concerns (mold, evaporation) Special concerns (mold, evaporation) Various light sources Various light sources Latent fingerprints Latent fingerprints Mobile crime labs or better yet crime scene search vehicle Mobile crime labs or better yet crime scene search vehicle

20. Chain of custody Continuity of possession; every person who touched it must be accounted for Continuity of possession; every person who touched it must be accounted for Standards for collecting, labeling, and submitting evidence forms are necessary for court Standards for collecting, labeling, and submitting evidence forms are necessary for court Labels include collectors initials, location of evidence, date of collection. Identification numbers must also be used Labels include collectors initials, location of evidence, date of collection. Identification numbers must also be used

21. Submission of Evidence Standard/reference samples Standard/reference samples Substance controls Substance controls Evidence submission form will detail the evidence collect and particular type of examination/analysis requested. Evidence submission form will detail the evidence collect and particular type of examination/analysis requested. Lab tech not bound by requests Lab tech not bound by requests

22. Common Types of Evidence Common Types of Evidence Common Types of Evidence Blood, semen, and saliva Blood, semen, and saliva Documents Documents Drugs Drugs Fibers Fibers Fingerprints Fingerprints Firearms and ammunition Firearms and ammunition Glass Glass Hair Hair Impressions Impressions Organs and physiological fluids Organs and physiological fluids Paint Paint Petroleum products Petroleum products Plastic bags Plastic bags Plastic, rubber, and other polymers Plastic, rubber, and other polymers Powder residues Powder residues Serial numbers Serial numbers Soil and minerals Soil and minerals Tool marks Tool marks Vehicle lights Vehicle lights Wood and other vegetative matter Wood and other vegetative matter

23. Examination of Physical Evidence Identification Identification Determining the identity of a substance with a near absolute certainty while ruling out other substances Determining the identity of a substance with a near absolute certainty while ruling out other substances Comparison Comparison Comparing the evidence to one or more selected references and drawing a conclusion about its origins. Comparing the evidence to one or more selected references and drawing a conclusion about its origins. Individual characteristics –properties of evidence that can be attributed to a common source with extremely high certainty. (eg. fingerprints, DNA, bullets) Individual characteristics –properties of evidence that can be attributed to a common source with extremely high certainty. (eg. fingerprints, DNA, bullets) Class characteristics – properties of evidence that can be associated with a group and never with a single source. ( eg. Blood type, tire marks) Class characteristics – properties of evidence that can be associated with a group and never with a single source. ( eg. Blood type, tire marks)

24. Significance of Physical Evidence Assessing the values of evidence Assessing the values of evidence Class characteristics of evidence is valuable in corroborating events. Class characteristics of evidence is valuable in corroborating events. Multiple class evidence can lead to a high level of certainty of origin Multiple class evidence can lead to a high level of certainty of origin Cautions and limitations of evidence Cautions and limitations of evidence A person can be exonerated or excluded from suspicion if evidence collected from the crime scene is different from the reference samples collected from the person. A person can be exonerated or excluded from suspicion if evidence collected from the crime scene is different from the reference samples collected from the person.

25. Forensic Databases One-on-one comparison requires a suspect One-on-one comparison requires a suspect Computerized databases help link evidence to people Computerized databases help link evidence to people Fingerprint databases – IAFIS Fingerprint databases – IAFIS DNA database – CoDIS DNA database – CoDIS Ballistics database – IBIS Ballistics database – IBIS Automative Paint database – PDQ Automative Paint database – PDQ Shoeprint database - SICaR Shoeprint database - SICaR

26. Crime-Scene Reconstruction The method used to support a likely sequence of events at a crime scene by observing and evaluating physical evidence and statements made by those involved with the incident The method used to support a likely sequence of events at a crime scene by observing and evaluating physical evidence and statements made by those involved with the incident Combined efforts of MEs, CSI, and law enforcement personnel Combined efforts of MEs, CSI, and law enforcement personnel Examples: was body moved, bullet trajectory, blood splatter Examples: was body moved, bullet trajectory, blood splatter

27. History Alphonse Bertillion (1883) – anthropometry Alphonse Bertillion (1883) – anthropometry Henry Fauld (1880) - first published on possible use of fingerprints Henry Fauld (1880) - first published on possible use of fingerprints Francis Galton (1892) – published Finger Prints described types of prints Francis Galton (1892) – published Finger Prints described types of prints Sir Edward Henry (1897) – classification system used today Sir Edward Henry (1897) – classification system used today FBI (1924) – new formed FBI held world’s largest fingerprint database FBI (1924) – new formed FBI held world’s largest fingerprint database

28. Fingerprint Principles 1. A fingerprint is an individual characteristic; no two fingerprints have been found to possess identical ridge characteristics 1. A fingerprint is an individual characteristic; no two fingerprints have been found to possess identical ridge characteristics No minimum number of comparisons to establish identity No minimum number of comparisons to establish identity 2. A fingerprint remains unchanged during an individual’s lifetime 2. A fingerprint remains unchanged during an individual’s lifetime Friction ridges and grooves created by dermal papillae Friction ridges and grooves created by dermal papillae Sweat glands on the ridges deposit perspiration and oils Sweat glands on the ridges deposit perspiration and oils Latent fingerprint – left by deposits and is invisible to the naked eye Latent fingerprint – left by deposits and is invisible to the naked eye 3. Fingerprints have general ridge patterns that permit them to be systematically classified. 3. Fingerprints have general ridge patterns that permit them to be systematically classified.

29. Categories of Fingerprints Loop – ridge lines enter one side of pattern and curve around to exit from the same side of pattern. (65%) Loop – ridge lines enter one side of pattern and curve around to exit from the same side of pattern. (65%) Ulnar loop – opens toward little finger Ulnar loop – opens toward little finger Radial loop – opens toward thumb Radial loop – opens toward thumb Ulnar LoopRadial Loop

30. Categories of Fingerprints Whorl – ridge lines rounded or circular and have two deltas(30-35%) Whorl – ridge lines rounded or circular and have two deltas(30-35%) Plain whorl Plain whorl Central pocket loop Central pocket loop Double loop Double loop Accidental loop Accidental loop

31. Categories of Fingerprints Arch – ridge lines enter print from one side and exit from the other (5%) Arch – ridge lines enter print from one side and exit from the other (5%) Plain Plain Tented Tented

32. Classification of Fingerprints Henry system – numerical system involving the presence or absence of the whorl pattern on each finger as part of the primary classification.. Henry system – numerical system involving the presence or absence of the whorl pattern on each finger as part of the primary classification.. This does not identify someone, only reduce the number of possible candidates This does not identify someone, only reduce the number of possible candidates AFIS – 10 print system that can search 500,000 stored ten-prints in 0.8 seconds AFIS – 10 print system that can search 500,000 stored ten-prints in 0.8 seconds Data entered now by Livescan rather than ink rolling. Data entered now by Livescan rather than ink rolling. Human decisions must still be made Human decisions must still be made Software incompatibilities among states Software incompatibilities among states

33. Methods of Detection Types of prints Types of prints Latent print Latent print Visible print – deposited ink, blood, dirt Visible print – deposited ink, blood, dirt Plastic print – impression in a soft surface Plastic print – impression in a soft surface Locating prints – RUVIS Locating prints – RUVIS

34. Developing Prints Powders Powders Charcoal Charcoal Magnetic Magnetic Fluorescent Fluorescent Chemicals Chemicals Iodine fuming (sublimation) Iodine fuming (sublimation) Ninhydrin Ninhydrin Physical developer (silver nitrate) Physical developer (silver nitrate) Super Glue fuming Super Glue fuming Alternate Light Sources/ LED Alternate Light Sources/ LED

35. Preservation of Developed Prints Photographs Photographs Print surface should be removed in its entirety (covered with cellophane) Print surface should be removed in its entirety (covered with cellophane) Lifted from surface with tape Lifted from surface with tape Digital imaging into pixels – allows adjustments to be made to enhance picture Digital imaging into pixels – allows adjustments to be made to enhance picture