1、 FORENSIC SCIENCE INTRODUCTIONCrime SceneInvestigation2Forensic ScienceDefinition: The application of scientific technology to supply accurate and objective information reflecting the events that occurred at a crime.What does a Forensic Scientist DO?Analyze physical evidenceProvide Expert TestimonyP

2、rovide training in the recognition, collection and preservation of physical evidenceComplex ReasoningIn Forensic ScienceDeductive (reasoning from the general to the particular) andInductive Reasoning (reasoning from detailed facts to general principles)ClassifyingComparing and ContrastingProblem Sol

3、vingAnalyzing PerspectivesConstructing SupportError Analysis4The History of Forensic ScienceSherlock Holmes: a fictional character developed by Sir Arthur Conan Doyle; used a great deal of forensic detectionMathieu Orfila: toxicology (the detection of poisons)Alphonse Bertillon: anthropometry (perso

4、nal identification through body measurements)Francis Galton: developed 1st fingerprint identification systemLeone Lattes: determined methods of using blood type as a means of identificationCalvin Goddard: firearms examinationAlbert Osborn: document examinationEdmund Locard: Developed the 1st police

5、labJ. Edgar Hoover: director of the FBI: Organized the 1st FBI Crime Lab in 19325Locards Exchange PrincipleWhenever 2 objects come in contact with one another, they exchange some material (dust particles, hair, dead skin cells)Locard strongly believed that every criminal can be connected to a crime

6、by dust particles carried from the scene6Branches of Forensic SciencePhysical science: Using chemistry, physics, and geology to ID and compare crime scene evidenceBiology: blood, body fluids, hairs and fibers, entomologyPathology, psychology, odontology, any many more!7CORPUS DELICTI“Body of the Cri

7、meYou must prove:that a crime occurredthat the person charged with the crime was responsible for the crimeTop Reasons for Committing a CrimeMoneyRevengeSexEmotion-love, hate, angerSource of EvidenceBodyPrimary and/or Secondary Crime SceneSuspect(s)84 Major FEDERAL Crime Labs:FBIDrug Enforcement Admi

8、nistration (DEA)Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF)US Postal Inspection ServiceMost states also have their own, smaller crime labs9General Crime Lab Servicesand the materials each unit analyzesPhysical Science Unit: drugs, glass, paint, explosives, etcBiology Unit: blood and ot

9、her bodily fluidsFirearms Unit: ballistics, comparisonsDocument Examination Unit: handwriting, typewriting, questioned documents (ransom notes, etc)Photography Unit: record all phyhsical evidence.Toxicology Unit: presence/absence of drugsLatent Fingerprint Unit: fingerprintsPathology Unit-10Forensic

10、 PathologyInvestigation of sudden unnatural, unexplained or violent deathsAnswer the questions:Who is the victim?What are the injuries, when did they occur, and how were they produced?5 manners of death: natural, homicide, suicide, accident, undetermined GO TO SLIDE 25.11Crime Scene TeamA group of p

11、rofessionals investigators, each trained in a variety of special disciplines.Team MembersFirst Police Officer on the sceneMedics (if necessary)Investigator(s)Medical Examiner (if necessary)Photographer and/or Field Evidence TechnicianLab ExpertspathologistserologistDNA experttoxicologistforensic odo

12、ntologistforensic anthropologistforensic psychologistforensic entomologistfirearm examinerbomb and arson expertdocument and handwriting expertsfingerprint expert12INVESTIGATORS“The wise forensic investigator will always remember that he must bring all of his life experiences and logic to find the tr

13、uth. This means common sense, informed intuition, and the courage to see things as they are. Then he must speak honestly about what it adds up to.Dr. Henry LeeChief Emeritus for Scientific Services and the former Commissioner of Public Safety for the state of Connecticut13First Officerat the SceneAA

14、ssess the crime sceneDDetain the witnessAArrest the perpetratorPProtect the crime sceneTTake notes14Eye Witness“Perception is reality.As a result an eye witness may not be the best source of crime scene information.A police composite may be developed from the witness testimony by a computer program

15、or forensic artist.Faces Composite Programby InterQuest15Crime SceneSearch PatternsSpiralGridTWO of FOUR PATTERNS16Crime SceneSearch PatternsStrip or LineQuadrant or ZoneTWO of FOUR PATTERNS17Crime SceneSketchDate: August 14, 2001Criminalist: Ann WilsonTime: 11:35Location: 4358 Rockledge DrSt. Louis

16、, Mo.A. Couch/sofaB. Female bodyC. KnifeD. Over turned LampE. ChairsF. TableG. FireplacecDEEEEEAGF18Crime Scene Mapping(outdoors)Azimuth-uses a compass beam to determine the location of each piece of evidenceTriangulation-uses two points at the crime scene to map each piece of evidenceCoordinate or

17、grid-divides the crime scene into squares for mapping.Suspended Polar Coordinate-for use in mapping evidence in a holeBaseline-set a north/south line and measures each piece of evidence from this line.AZIMUTHDetermines:DirectionDistanceElevationTRIANGULATIONMeasure from A to B and then to the eviden

18、ce in a triangular shape.Coordinate or Grid MappingSet a north/south line from a datum point established by a GPS.Make it a perfect square (4 x 4) by shooting the hypotenuse and setting in stakes every foot or meter.Measure and map the location of each piece of evidence. Then collect evidence and pl

19、ace in containers by grid.Baseline MappingSet a north/south line from the furthest most points of the crime scene. Then measure each piece of evidence from that baseline. Evidence will need a numerical measurement where the piece begins, ends and in the middle.EvidenceBaselineSuspended Polar Coordin

20、ateMeasure and map each layer of evidence as you move down the hole. Use the compass readings from the top to measure degrees and a tank dipping line to measure depth.24MAPPING TECHNOLOGYThe latest technology includes this Nikon Tsunami with computer. The exact location of all crime evidence can be

21、determined and directly loaded into a computer to produce a crime scene map. Cost = $35,000 for the set.25Physical EvidenceTransient Evidence-temporary; easily changed or lost; usually observed by the first officer at the sceneOdor-putrefaction, perfume, gasoline, urine, burning, explosives, cigaret

22、te or cigar smokeTemperature-of room, car hood, coffee, water in a bathtub; cadaverImprints and indentations-footprints; teeth marks in perishable foods; tire marks on certain surfacesMarkings26Physical Evidence (cont)Pattern or Transfer Evidence-produced by direct contact between a person and an ob

23、ject or between two objects. There are several ways (at least 7) of classifying evidence. In this class, we will use:BiologicalChemicalPhysicalMiscellaneous27Biological EvidenceBloodSemenSalivaSweat/TearsHairBoneTissuesUrineFecesAnimal Material InsectsBacterial/Fungal28Chemical EvidenceFibersGlassSo

24、ilGunpowderMetalMineralNarcoticsDrugsPaperInkCosmeticsPaintPlasticLubricantsFertilizer29Physical (impression)FingerprintsFootprintsShoe printsHandwritingFirearmsPrintingNumber restorationTire marksTool marksTypewriting30MiscellaneousLaundry marksVoice analysisPolygraphPhotographyStress evaluationPys

25、cholinguistic analysisVehicle identification31Physical Evidence (cont)Conditional Evidence-produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances within a particular event.Light-headlight; lighting conditionsSmoke-color, direction

26、of travel, density, odorFire-color and direction of the flames, speed of spread, temperature and condition of fire32Conditional Evidence (cont.)Location-of injuries or wounds; of bloodstains; of the victims vehicle;of weapons or cartridge cases; of broken glass, etc.Vehicles-doors locked or unlocked

27、, windows opened or closed; radio off or on (station); odometer mileageBody-position; types of wounds; rigor, livor and algor mortisScene-condition of furniture, doors and windows; any disturbance or signs of a struggle.33 Evidence CharacteristicsClass-common to a group of objects or personsIndividu

28、al-can be identified with a particular person or source.ABO Blood TypingBlood DNA Typing34Medical Examiner vs the CoronerA medical examiner is a medical doctor, usually a pathologist and is appointed by the governing body of the area. There are 7 medical examiners in the state of Missouri and 400 fo

29、rensic pathologists throughout the U.S.A coroner is an elected official who usually has no special medical training. In four states the coroner is a medical doctor.35Medical ExaminersResponsibilitiesIdentify the deceasedEstablish the time and date of deathDetermine a medical cause of death-the injur

30、y or disease that resulted in the person dyingDetermine the mechanism of death-the physiological reason that the person diedClassify the manner of deathNaturalAccidentalSuicideHomicideUndeterminedNotify the next of kin36THE BODYRigor Mortis Temperature Stiffness Time Since of body of body DeathWarmW

31、armColdColdNot stiffStiffStiffNot stiffNot dead more than 3 hrsDead between 3 and 8 hrsDead 8 to 36 hoursDead more than 36 hours37THE BODYLivor MortisLivor mortis is the settling of the blood, causing the skin to change colors.Lividity indicates the position of the body after death. When lividity be

32、comes fixed, then the distribution of the lividity pattern will not change even if the bodys position is altered. Lividity usually becomes fixed between 10 and 15 hours after death.38THE BODYAlgor MortisAlgor mortis is body temperature. Average human body temperature: 98.6 F (37 C)39Time Frame of De

33、athConditionAppearancePeriphery blood drying30 min to 2 hrsBlue-green discoloration of skinRight and left area of abdomen24 hoursEntire abdomen36 hoursBloating36 to 48 hoursSkin slippage4 to7 daysAbsence of smell from bonesmore than 1 year 40Time Frame of DeathEyeball ChangesConditionAppearance Corn

34、ea drying (eyes open)minutesCornea drying (eyes closed)2 hoursCorneal cloudiness (eyes open)less than 2 hoursCorneal cloudiness (eyes closed) 12 to 24 hoursEyeball collapsemore than 24 hrs41One can die of a massive hemorrhage (the mechanism of death) due to a fall (cause of death) as a result of bei

35、ng pushed (homicide), jumping (suicide), falling (accident), or not being able to tell which (undetermined). All of which are manners of death. THEREFORE,42CRIME+=What Happened?Why Did ItHappened?Who DidIt?Crime Scene Evidence Collection Witness, Suspect and Motive DevelopmentPost Scene Evidence Processing Cause, manner, time of deathInvestigative Stage Profiling Means Motive OpportunityIdentificationand Arrest ofSuspect43Forensic InvestigationsInclude some or