forensic science criminalistics chapter 1: introduction
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Forensic ScienceForensic Science
CriminalisticsCriminalistics
Chapter 1:Chapter 1:
IntroductionIntroduction
What is Forensic Science?What is Forensic Science?
The application of science and technology to The application of science and technology to those criminal and civil laws that are those criminal and civil laws that are
enforced by police agencies in a criminal enforced by police agencies in a criminal justice system.justice system.
Major Sciences Involved in Major Sciences Involved in ForensicsForensics
Chemistry:Chemistry: examines the chemical makeup of substances examines the chemical makeup of substances
found at the crime scenefound at the crime scene
Biology:Biology: examines the biological properties of examines the biological properties of
substances found at the crime scenesubstances found at the crime scene
Major Sciences Involved in Major Sciences Involved in ForensicsForensics
Physics:Physics: examines the movement or impact of examines the movement or impact of
materials at the crime scenematerials at the crime scene
Geology:Geology: examines the earth’s components when examines the earth’s components when
important to the crime scene investigationimportant to the crime scene investigation
History of ForensicsHistory of Forensics
Sir Arthur Conan DoyleSir Arthur Conan DoyleFictional character –Sherlock HolmesFictional character –Sherlock HolmesThe character, Sherlock Holmes, first applied The character, Sherlock Holmes, first applied
these principles in Doyle’s novels:these principles in Doyle’s novels:SerologySerologyFingerprintingFingerprintingFirearm IdentificationFirearm IdentificationQuestioned-document examinationQuestioned-document examination
History of ForensicsHistory of Forensics
Mathieu Orfila (1787-1853)Mathieu Orfila (1787-1853)Father of Forensic ToxicologyFather of Forensic ToxicologySpanish native—taught medicine in FranceSpanish native—taught medicine in FrancePublished “The Detection of Poisons and Published “The Detection of Poisons and
Their Effects on Animals” which established Their Effects on Animals” which established Forensic Toxicology as a legitimate scientific Forensic Toxicology as a legitimate scientific endeavorendeavor
History of ForensicsHistory of Forensics
Alphonse Bertillon (1853-1914)Alphonse Bertillon (1853-1914)Father of Personal Identification or Criminal Father of Personal Identification or Criminal
IdentificationIdentification The science of The science of anthropometry:anthropometry: a systematic a systematic
method of taking body measurementsmethod of taking body measurementsAnthropometry was eventually replaced by Anthropometry was eventually replaced by
fingerprinting in the early 1900sfingerprinting in the early 1900s
History of ForensicsHistory of Forensics
Francis Galton (1822-1911)Francis Galton (1822-1911)Studied fingerprints and developed a method Studied fingerprints and developed a method
of classifying themof classifying themProved the uniqueness of individual Proved the uniqueness of individual
fingerprints and their use for personal fingerprints and their use for personal identificationidentification
His ideas describe the principles used today His ideas describe the principles used today in fingerprintingin fingerprinting
History of ForensicsHistory of Forensics
Leone Lattes (1887-1954)Leone Lattes (1887-1954)Developed the concept that blood typing Developed the concept that blood typing
could be a useful identification tool in criminal could be a useful identification tool in criminal investigationinvestigation
Devised a simple procedure for determining Devised a simple procedure for determining the blood group from a dried blood stainthe blood group from a dried blood stain
History of ForensicsHistory of Forensics
Calvin Goddard (1891-1955)Calvin Goddard (1891-1955)Colonel in the United States ArmyColonel in the United States ArmyFirst used the Comparison Microscope to First used the Comparison Microscope to
determine if a bullet had been fired from a determine if a bullet had been fired from a certain firearmcertain firearm
Established the Comparison Microscope as Established the Comparison Microscope as an indispensable tool in forensic an indispensable tool in forensic investigationsinvestigations
History of ForensicsHistory of Forensics
Albert S. Osborn (1858-1946)Albert S. Osborn (1858-1946)Development of the fundamental principles of Development of the fundamental principles of
document examinationdocument examinationWas responsible for the acceptance of Was responsible for the acceptance of
document examinations as scientific evidence document examinations as scientific evidence by courts of lawby courts of law
Authored Authored “Questioned Documents” –a book “Questioned Documents” –a book still used in the field of document examination still used in the field of document examination todaytoday
History of ForensicsHistory of Forensics
Walter McCrone (1916-2002)Walter McCrone (1916-2002)Applied using microscopes to all fields of Applied using microscopes to all fields of
forensic investigationsforensic investigationsTaught numerous forensic scientists how to Taught numerous forensic scientists how to
use quantitative analysis methods in forensic use quantitative analysis methods in forensic investigationsinvestigations
History of ForensicsHistory of Forensics
Hans Gross (1847-1915)Hans Gross (1847-1915)Authored the first treatise describing the Authored the first treatise describing the
application of scientific disciplines to the field application of scientific disciplines to the field of criminal investigationof criminal investigation
Detailed the assistance that investigators Detailed the assistance that investigators could expect from the numerous fields of could expect from the numerous fields of sciencescience
History of ForensicsHistory of Forensics
Edmond Locard (1877-1966)Edmond Locard (1877-1966)Strong advocate of the use of the scientific Strong advocate of the use of the scientific
method in criminal investigationmethod in criminal investigationBackground in Medicine and in LawBackground in Medicine and in LawTaught how scientific principles could be Taught how scientific principles could be
developed into a workable crime laboratorydeveloped into a workable crime laboratoryFamous for Famous for Locard’s Exchange PrincipleLocard’s Exchange Principle
Locard’s Exchange PrincipleLocard’s Exchange Principle
The exchange of materials between two The exchange of materials between two objects that occurs whenever two objects objects that occurs whenever two objects
come into contact with one anothercome into contact with one another
Locard’s Exchange PrincipleLocard’s Exchange Principle
Examples:Examples:Metal particles carried on clothing from a Metal particles carried on clothing from a
crime scene can link a suspect to a crimecrime scene can link a suspect to a crimeSoil samples found on the vehicle of a Soil samples found on the vehicle of a
suspect can link the suspect to a crime scenesuspect can link the suspect to a crime scenePlant material found on cars or clothing can Plant material found on cars or clothing can
link a suspect to a crime scenelink a suspect to a crime scene
Beginnings of Crime LabsBeginnings of Crime Labs
The oldest crime lab in the United States The oldest crime lab in the United States was established by the Los Angeles Police was established by the Los Angeles Police Department in 1923 under the Director Department in 1923 under the Director August VollmerAugust Vollmer
The Federal Bureau of The Federal Bureau of InvestigationInvestigation
19321932Director: J. Edgar HooverDirector: J. Edgar HooverOrganized a national crime laboratory to Organized a national crime laboratory to
provide forensic services to all law provide forensic services to all law enforcement agencies in the countryenforcement agencies in the country
The Federal Bureau of The Federal Bureau of InvestigationInvestigation
The FBI Laboratory is now the world’s The FBI Laboratory is now the world’s largest forensic laboratory, performing largest forensic laboratory, performing over one million examinations per yearover one million examinations per year
The Federal Bureau of The Federal Bureau of InvestigationInvestigation
Opened the Opened the Forensic Science Research Forensic Science Research and Training Centerand Training Center in 1981in 1981
Center is dedicated to conducting Center is dedicated to conducting research and developing new and reliable research and developing new and reliable scientific methods that can be applied to scientific methods that can be applied to forensic scienceforensic science
The Organization of a The Organization of a Crime LaboratoryCrime Laboratory
Crime LabsCrime Labs
Can be under the direction of …Can be under the direction of …The Police DepartmentThe Police DepartmentThe Prosecutors or District Attorney’s OfficeThe Prosecutors or District Attorney’s OfficeThe Coroner or Medical Examiner’s OfficeThe Coroner or Medical Examiner’s OfficeUniversities as independent testing facilitiesUniversities as independent testing facilities
Crime LabsCrime Labs
Range in size and in the number of staff Range in size and in the number of staff membersmembers
Can be classified under several Can be classified under several jurisdictionsjurisdictions FederalFederalStateStateCountyCountyMunicipalMunicipal
Crime LabsCrime Labs
There are approximately 320 public crime There are approximately 320 public crime labs operating in various jurisdictionslabs operating in various jurisdictions
These crime labs range being able to These crime labs range being able to perform a diversity of tasks to very perform a diversity of tasks to very specialized scientific testingspecialized scientific testing
Growth of the Crime LabGrowth of the Crime Lab
Some Reasons:Some Reasons:Courts placing greater emphasis on scientific Courts placing greater emphasis on scientific
evidenceevidenceEmphasis on thorough and complete police Emphasis on thorough and complete police
investigationsinvestigations Increase in modern technology and types of Increase in modern technology and types of
testing that can be completedtesting that can be completed
Growth of the Crime LabGrowth of the Crime Lab
Major Reasons:Major Reasons: Increase in the crime rates in the United Increase in the crime rates in the United
StatesStatesEven though many crimes do not require forensic Even though many crimes do not require forensic
evaluation of evidenceevaluation of evidence
Growth of the Crime LabGrowth of the Crime Lab
Major Reasons:Major Reasons:The increased number of drug-related arrestsThe increased number of drug-related arrests
All seizures must be sent to the lab for All seizures must be sent to the lab for confirmation of chemical composition of the confirmation of chemical composition of the substance substance
More drug arrests=Larger case loads of drug-More drug arrests=Larger case loads of drug-related specimensrelated specimens
Growth of the Crime LabGrowth of the Crime Lab
Major Reasons:Major Reasons:The advent of DNA ProfilingThe advent of DNA Profiling
Labor-intensive tests for DNA analysisLabor-intensive tests for DNA analysis May come from blood evidenceMay come from blood evidence May come from saliva or other bodily fluidsMay come from saliva or other bodily fluids May come from bite marks, cigarette butts, hair, etc.May come from bite marks, cigarette butts, hair, etc.
Federal Crime Labs in the U.S.Federal Crime Labs in the U.S.
Will assist any local agency that requests Will assist any local agency that requests assistance in investigative mattersassistance in investigative matters
Federal Crime Labs in the U.S.Federal Crime Labs in the U.S.
Federal Bureau of Investigation (FBI)Federal Bureau of Investigation (FBI)Housed under the Department of JusticeHoused under the Department of JusticeResponsibilities:Responsibilities:
Broad, investigative powers that exceed Broad, investigative powers that exceed jurisdictions of state and local authoritiesjurisdictions of state and local authorities
Expertise and technology support for criminal Expertise and technology support for criminal investigationsinvestigations
Federal Crime Labs in the U.S.Federal Crime Labs in the U.S.
Drug Enforcement Agency (DEA)Drug Enforcement Agency (DEA)Housed under The Department of JusticeHoused under The Department of JusticeResponsibilitiesResponsibilities
Analysis of drugs seized in violation of federal laws Analysis of drugs seized in violation of federal laws that regulate the production, sale, and that regulate the production, sale, and transportation of drugs in the U.S.transportation of drugs in the U.S.
Federal Crime Labs in the U.S.Federal Crime Labs in the U.S.
Bureau of Alcohol, Tobacco, Firearms, Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)and Explosives (ATF)
Housed under The Department of JusticeHoused under The Department of JusticeResponsibilities:Responsibilities:
Analyzing alcoholic beverages and documents Analyzing alcoholic beverages and documents relating to tax law enforcement relating to tax law enforcement
Examining weapons, explosive devices, and Examining weapons, explosive devices, and evidence relating to the Gun Control Act of 1968 evidence relating to the Gun Control Act of 1968 and the Organized Crime Control Act of 1970and the Organized Crime Control Act of 1970
Federal Crime Labs in the U.S.Federal Crime Labs in the U.S.
U.S. Postal Inspection ServicesU.S. Postal Inspection ServicesHoused under The Department of JusticeHoused under The Department of JusticeResponsibilities:Responsibilities:
Investigates criminal acts relating to the postal Investigates criminal acts relating to the postal serviceservice
State Crime Labs in the U.S.State Crime Labs in the U.S.
Most states have crime labs to assist local Most states have crime labs to assist local law enforcement agencies that do not law enforcement agencies that do not
have easy access to a crime labhave easy access to a crime lab
State Crime Labs in the U.S.State Crime Labs in the U.S.
Some states, such as Alabama, have Some states, such as Alabama, have developed a comprehensive statewide developed a comprehensive statewide
system of crime labs with satellite facilitiessystem of crime labs with satellite facilities
Maximizes access to lab services without Maximizes access to lab services without duplicating services at each siteduplicating services at each site
Sharing of expertise and equipmentSharing of expertise and equipment
Services of the Crime LabServices of the Crime Lab
Variation in ServicesVariation in Services
There are many different services There are many different services available in different crime labsavailable in different crime labs
Reasons:Reasons:Variations in local lawsVariations in local lawsDifferent capabilities and functions of the Different capabilities and functions of the
organization in which the lab is attachedorganization in which the lab is attachedBudgetary and staffing limitationsBudgetary and staffing limitations
Full-Service Crime Lab: 5 PartsFull-Service Crime Lab: 5 Parts
Physical Science UnitPhysical Science UnitApplies the principles and techniques of Applies the principles and techniques of
chemistry, physics, and geology to chemistry, physics, and geology to identification and comparison of crime-scene identification and comparison of crime-scene evidenceevidence
Examples:Examples:Drug Chemistry IdentificationDrug Chemistry IdentificationSoil/Mineral AnalysisSoil/Mineral AnalysisPhysical Properties of Trace EvidencePhysical Properties of Trace Evidence
Full-Service Crime Lab: 5 PartsFull-Service Crime Lab: 5 Parts
Biology UnitBiology UnitStaffed with biologists and biochemists that Staffed with biologists and biochemists that
apply their knowledge to the identification of apply their knowledge to the identification of biological aspects of a crime scenebiological aspects of a crime scene
Examples:Examples:Identification and DNA profiling of dried blood Identification and DNA profiling of dried blood
stains and other bodily fluidsstains and other bodily fluidsHair and fiber comparisonHair and fiber comparisonIdentification of plant materialIdentification of plant material
Full-Service Crime Lab: 5 PartsFull-Service Crime Lab: 5 Parts
Firearms UnitFirearms UnitResponsible for the examination of firearms, Responsible for the examination of firearms,
discharged bullets, cartridge cases, shotgun discharged bullets, cartridge cases, shotgun shells, and ammunition of all typesshells, and ammunition of all types
Examples:Examples:Examination of ammunition casingsExamination of ammunition casingsFirearm or gunpowder residueFirearm or gunpowder residueTarget lengthTarget lengthToolmarksToolmarks
Full-Service Crime Lab: 5 PartsFull-Service Crime Lab: 5 Parts
Document Examination UnitDocument Examination UnitStudies the typewriting and handwriting on Studies the typewriting and handwriting on
questioned documents to determine questioned documents to determine authenticity and/or sourceauthenticity and/or source
Examples:Examples:Handwriting identificationHandwriting identificationAnalysis of ink or paperAnalysis of ink or paperIndentationsIndentationsErasure marksErasure marks
Full-Service Crime Lab: 5 PartsFull-Service Crime Lab: 5 Parts
Photography UnitPhotography UnitUsed to examine and record physical Used to examine and record physical
evidenceevidenceExamples:Examples:
Digital imagingDigital imagingInfrared imagingInfrared imagingUltraviolet imagingUltraviolet imagingX-ray photographyX-ray photography
Crime Lab Optional ServicesCrime Lab Optional Services
Toxicology Unit: Toxicology Unit: Determines the presence or absence of drugs Determines the presence or absence of drugs
or poisonsor poisonsLatent Fingerprint UnitLatent Fingerprint Unit
Processes and examines evidence for latent Processes and examines evidence for latent fingerprintsfingerprints
Polygraph UnitPolygraph UnitAdministers lie detector tests to suspectsAdministers lie detector tests to suspects
Crime Lab Optional ServicesCrime Lab Optional Services
Voiceprint Analysis UnitVoiceprint Analysis UnitAnalyzes tape-recorded messages or Analyzes tape-recorded messages or
telephoned threats telephoned threats Evidence Collection UnitEvidence Collection Unit
Collects and preserves evidence at the crime Collects and preserves evidence at the crime scenescene
The Functions of the The Functions of the Forensic ScientistForensic Scientist
Forensic ScientistsForensic Scientists
Must be skilled in applying the principles and Must be skilled in applying the principles and techniques of the physical and natural techniques of the physical and natural
sciences to the analysis of many types of sciences to the analysis of many types of evidence that may be recovered at a crime evidence that may be recovered at a crime
scenescene
Forensic ScientistsForensic Scientists
Must have a firm, scientific foundation and Must have a firm, scientific foundation and follow specific procedures in order for follow specific procedures in order for
evidence to be admissible in courtevidence to be admissible in court
Frye v. United StatesFrye v. United States
Court case that established what type of Court case that established what type of rules scientific evidence have to followrules scientific evidence have to followSaid that scientific procedures will only be Said that scientific procedures will only be
allowed in a court of law if the procedures allowed in a court of law if the procedures used are used are “generally accepted by the scientific “generally accepted by the scientific community”community”
Helps establish the accuracy and validity of Helps establish the accuracy and validity of the tests and the results easy to understand the tests and the results easy to understand by all scientistsby all scientists
““Generally Accepted Procedures”Generally Accepted Procedures”
How are “How are “generally accepted procedures” generally accepted procedures” determined?determined?Expert witnessesExpert witnessesBooksBooksDocumented studies Documented studies Case historyCase history
Daubert v. Merrell Dow Daubert v. Merrell Dow Pharmaceutical, Inc.Pharmaceutical, Inc.
Court case in 1993Court case in 1993Asserted that “general acceptance” is not Asserted that “general acceptance” is not
an absolute prerequisite for admissibilityan absolute prerequisite for admissibilityThe judge in the case can be a The judge in the case can be a
“gatekeeper” in deciding the admissibility “gatekeeper” in deciding the admissibility and reliability of scientific evidence that is and reliability of scientific evidence that is presented in a courtroompresented in a courtroom
Daubert Precedence Daubert Precedence GuidelinesGuidelines
Guidelines to gauge the scientific evidenceGuidelines to gauge the scientific evidenceWhether or not the method has been or can Whether or not the method has been or can
be testedbe testedWhether or not the method has been Whether or not the method has been
published or reviewed by others in the fieldpublished or reviewed by others in the fieldThe technique’s potential rate of errorThe technique’s potential rate of errorStandards of operational proceduresStandards of operational proceduresAcceptance in the general scientific Acceptance in the general scientific
communitycommunity
Kumho Tire Co. v. CarmichaelKumho Tire Co. v. Carmichael
The trial judge’s “gatekeeping” rule applies The trial judge’s “gatekeeping” rule applies to not only scientific evidence but also to to not only scientific evidence but also to
expert testimonyexpert testimony
Coppolino v. StateCoppolino v. State
Widened the discretion of the trial judgeWidened the discretion of the trial judgeNew scientific tests can be used in New scientific tests can be used in
evidence if no other tests can be or ever evidence if no other tests can be or ever have been performedhave been performedMust have valid principles and techniquesMust have valid principles and techniquesGive examiners the flexibility to develop new Give examiners the flexibility to develop new
and better methods of testing samplesand better methods of testing samples
What is an Expert Witness?What is an Expert Witness?
Expert witnessesExpert witnesses
Have knowledge, skill, experience, training, or Have knowledge, skill, experience, training, or education that lends itself directly to education that lends itself directly to understanding of scientific evidenceunderstanding of scientific evidence
What is an Expert Witness?What is an Expert Witness?
Expert witnesses are “qualified” for Expert witnesses are “qualified” for competence for testimony in a courtroom competence for testimony in a courtroom by:by:Degrees awardedDegrees awardedSpecial coursesSpecial coursesProfessional societiesProfessional societiesPublicationsPublicationsOccupational experienceOccupational experience
What is an Expert Witness?What is an Expert Witness?
Most experts Most experts do notdo not have Forensic have Forensic Science degreesScience degreesMost have degrees in specific science Most have degrees in specific science
disciplinedisciplineTraining and experience is also a large part of Training and experience is also a large part of
being “qualified” as an expert witnessbeing “qualified” as an expert witness
More about experts…More about experts…
Experts are the only people who may give Experts are the only people who may give testimony as opinions in courttestimony as opinions in courtOpinions must be based on facts and dataOpinions must be based on facts and dataOpinions must be based on reliable principles Opinions must be based on reliable principles
and methodsand methodsOpinions must apply the facts and principles Opinions must apply the facts and principles
directly to the case at handdirectly to the case at hand
Expert Witness TestimonyExpert Witness Testimony
Evaluate evidence that the court lacks Evaluate evidence that the court lacks expertise to doexpertise to do
Express an opinion of the significance of Express an opinion of the significance of the findingsthe findings
May be accepted or ignored in jury May be accepted or ignored in jury deliberationsdeliberations
Experts have Experts have no absolute certaintyno absolute certainty—their —their opinions come from training or experienceopinions come from training or experience
Opposing an Expert WitnessOpposing an Expert Witness
Weakness in background knowledge Weakness in background knowledge and/or educational experienceand/or educational experience
Inability to explain data clearly and Inability to explain data clearly and logicallylogically
Suitable qualifications are subjectiveSuitable qualifications are subjectiveDemeanor of the expert witness in the Demeanor of the expert witness in the
courtroomcourtroom
Lay v. Expert WitnessesLay v. Expert Witnesses
Expert witnesses may express opinions in Expert witnesses may express opinions in the courtroomthe courtroomMay or may not be dismissed by the jury or May or may not be dismissed by the jury or
judgejudgeLay witnesses may only express facts in Lay witnesses may only express facts in
the courtroomthe courtroomFacts must be taken into account by the jury Facts must be taken into account by the jury
or judgeor judge
Evidence Collection TeamEvidence Collection Team
Evidence Collection is Important!Evidence Collection is Important!
Must be collected correctly and preservedMust be collected correctly and preservedSome labs have Evidence Collection Some labs have Evidence Collection
Teams or Crime Scene InvestigatorsTeams or Crime Scene InvestigatorsTrained by lab staff to gather important Trained by lab staff to gather important
physical evidence at the scenephysical evidence at the sceneWork in the lab to continue their exposure to Work in the lab to continue their exposure to
the forensic proceduresthe forensic proceduresUse proper tools and supplies for collection Use proper tools and supplies for collection
and packaging of evidenceand packaging of evidence
Collecting Evidence Collecting Evidence
Sometimes specialized teams aren’t Sometimes specialized teams aren’t available for evidence collectionavailable for evidence collection
Detectives can also collect evidenceDetectives can also collect evidenceEffective based on training and experienceEffective based on training and experienceClassroom knowledge is necessary but experience Classroom knowledge is necessary but experience
is bestis best
Collecting EvidenceCollecting Evidence
Every officer should be trained in fieldworkEvery officer should be trained in fieldworkSome officers specialize in different fieldsSome officers specialize in different fields
TrafficTrafficPatrolPatrolInvestigationInvestigationJuvenile ControlJuvenile ControlEvidence CollectionEvidence Collection
All Officers Should Be FamiliarAll Officers Should Be Familiar
Classroom LecturesClassroom LecturesForensic Lab ToursForensic Lab ToursManuals for methods of submission of Manuals for methods of submission of
evidence to the labevidence to the lab
Appendix I of your book explains some Appendix I of your book explains some evidence collection and packaging evidence collection and packaging
proceduresprocedures
Other Forensic Science Other Forensic Science ServicesServices
Forensic PathologyForensic Pathology
Field that involves the investigation of Field that involves the investigation of sudden, unnatural, unexplained, or violent sudden, unnatural, unexplained, or violent deathsdeaths
Involve the Medical Examiner or Coroner Involve the Medical Examiner or Coroner and generally perform and generally perform autopsiesautopsies on on victimsvictimsAutopsyAutopsy: the medical dissection and : the medical dissection and
examination of a body in order to determine examination of a body in order to determine the cause of deaththe cause of death
Forensic PathologyForensic Pathology
Must answer the questions…Must answer the questions…Who is the victim?Who is the victim?What injuries are present?What injuries are present?When did the injuries occur?When did the injuries occur?Why and how were the injuries produced?Why and how were the injuries produced?
Forensic PathologyForensic Pathology
Must determine the Must determine the mannermanner of death of the of death of the victimvictim
Manners of deathManners of deathNatural Natural HomicideHomicideSuicideSuicideAccidentAccidentUndeterminedUndetermined
Determining Time of DeathDetermining Time of Death
Stages of DecompositionStages of DecompositionRigor Mortis: Rigor Mortis:
occurs after death and results in the shortening of occurs after death and results in the shortening of muscle tissue and the stiffening of body parts in muscle tissue and the stiffening of body parts in the position they are in when death occursthe position they are in when death occurs
Happens in the first 24 hours and disappears Happens in the first 24 hours and disappears within 36 hourswithin 36 hours
Determining Time of DeathDetermining Time of DeathStages of DecompositionStages of Decomposition
Livor Mortis:Livor Mortis:Occurs in the early stages of decomposition and Occurs in the early stages of decomposition and
results when the heart stops pumping and blood results when the heart stops pumping and blood pools in the parts of the body closest to the groundpools in the parts of the body closest to the ground
Skin will appear dark blue or purple in these areasSkin will appear dark blue or purple in these areasCondition appears immediately and continues for Condition appears immediately and continues for
up to 12 hours after deathup to 12 hours after deathSkin will not appear discolored in areas where the Skin will not appear discolored in areas where the
body is restricted by either clothing or an object body is restricted by either clothing or an object pressing against the body pressing against the body
Determining Time of DeathDetermining Time of Death
Stages of Decomposition:Stages of Decomposition:Algor Mortis:Algor Mortis:
Process in which the body temperature continually Process in which the body temperature continually cools after death until it reaches the ambient or the cools after death until it reaches the ambient or the temperature of its’ surroundingstemperature of its’ surroundings
General rule: the body will lose heat, beginning an General rule: the body will lose heat, beginning an hour after death, at a rate of 1 to 1.5 degrees hour after death, at a rate of 1 to 1.5 degrees Fahrenheit per hour until the environmental Fahrenheit per hour until the environmental temperature is reachedtemperature is reached
Influenced by weather/clothing conditionsInfluenced by weather/clothing conditions
Determining Time of DeathDetermining Time of Death
Potassium levels in the ocular fluidPotassium levels in the ocular fluidAfter death, cells release potassium into the After death, cells release potassium into the
liquid behind the eye liquid behind the eye By analyzing the amount of potassium present By analyzing the amount of potassium present
at various intervals after death, the rate of at various intervals after death, the rate of potassium release can be determinedpotassium release can be determined
Can help the pathologist to Can help the pathologist to approximateapproximate the the time of deathtime of death
Forensic AnthropologyForensic Anthropology
Identification and examination of skeletal Identification and examination of skeletal remainsremains
May reveal personal attributes such as May reveal personal attributes such as origin, sex, age, race, and/or injuryorigin, sex, age, race, and/or injury
Facial reconstructionFacial reconstructionMay be able to identify mass victims of May be able to identify mass victims of
disaster through skeletal remainsdisaster through skeletal remains
Forensic EntomologyForensic Entomology
The study of insects and their relation to a The study of insects and their relation to a criminal investigationcriminal investigation
As decomposition occurs, insects arrive on As decomposition occurs, insects arrive on the carcass in a regular time intervalthe carcass in a regular time interval
May help determine time of deathMay help determine time of deathResults may be effected by geographical Results may be effected by geographical
location, climate, and weather conditionslocation, climate, and weather conditions
Forensic PsychiatryForensic Psychiatry
Area in which the relationship between Area in which the relationship between human behavior and legal proceedings are human behavior and legal proceedings are examinedexamined
Civil cases: competency to make Civil cases: competency to make decisionsdecisions
Criminal cases: competency to stand trialCriminal cases: competency to stand trialProfilers: track the behavior of criminals Profilers: track the behavior of criminals
based on patterns and types of crimesbased on patterns and types of crimes
Forensic EngineeringForensic Engineering
Concerned with failure analysis, accident Concerned with failure analysis, accident reconstruction, and causes and origins of reconstruction, and causes and origins of fires or explosionsfires or explosions
Focus mainly on the logical sequence and Focus mainly on the logical sequence and main cause of an accident or crimemain cause of an accident or crime
Also attempts to determine who or what is Also attempts to determine who or what is responsible for the cause of an accident or responsible for the cause of an accident or crimecrime
Forensic OdontologyForensic Odontology
Provide information about the identification Provide information about the identification of victims when the body is left in an of victims when the body is left in an unrecognizable stateunrecognizable state
Dental recordsDental recordsCharacteristics of teethCharacteristics of teethTeeth alignmentTeeth alignmentOverall structure of the mouthOverall structure of the mouth
Bite mark analysis in assault casesBite mark analysis in assault cases
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