Chapter 8 – Crime and Criminal Law Unit 3 – Criminal Law Crime Scene Investigation

Chapter 8 – Crime and Chapter 8 – Crime and Criminal LawCriminal LawUnit 3 – Criminal LawUnit 3 – Criminal Law

Crime Scene InvestigationCrime Scene Investigation

Learning Goal for TodayLearning Goal for Today

By the end of the lesson(s), students By the end of the lesson(s), students will be able to discuss police will be able to discuss police investigative and evidence gathering investigative and evidence gathering techniquestechniques

ExpectationsExpectations

By the end of this lesson, students By the end of this lesson, students will:will:

……explain the processes of police explain the processes of police investigation, arrest, search, and investigation, arrest, search, and interrogation of suspectsinterrogation of suspects

AgendaAgenda

Crime Scene InvestigationCrime Scene Investigation FingerprintsFingerprints Trace ElementsTrace Elements Gunshot ResidueGunshot Residue DNADNA

IntroductionIntroduction

Chain of events from crime to trial is Chain of events from crime to trial is subject to the laws of criminal proceduresubject to the laws of criminal procedure

Laws balance two sometimes conflicting Laws balance two sometimes conflicting objectives: to discover the truth about a objectives: to discover the truth about a criminal event and to protect civil criminal event and to protect civil libertiesliberties

Rules of criminal procedure mark the Rules of criminal procedure mark the boundary between legitimate police boundary between legitimate police investigative practices and a person’s investigative practices and a person’s right to liberty, privacy and personal right to liberty, privacy and personal securitysecurity

Introduction (Cont’d)Introduction (Cont’d)

Reflect the belief that state power Reflect the belief that state power should be limitedshould be limited

That the rule of law applies as much to That the rule of law applies as much to police as to people accused of crimespolice as to people accused of crimes

That the ends do not always justify the That the ends do not always justify the meansmeans

Charter of Rights and Freedoms Charter of Rights and Freedoms confirms our commitment to fair confirms our commitment to fair process making criminal procedure a process making criminal procedure a matter of constitutional lawmatter of constitutional law


Investigation and evidence collection Investigation and evidence collection and securing of evidence huge and securing of evidence huge responsibilityresponsibility

Lapses can derail a trial or result in a Lapses can derail a trial or result in a miscarriage of justicemiscarriage of justice

Crime scene is a rich source of Crime scene is a rich source of evidenceevidence

Crime scene has boundariesCrime scene has boundaries Accidental contamination is an Accidental contamination is an

concernconcern

Crime SceneCrime Scene

Protect the area from accidental or Protect the area from accidental or intentional contamination by anyone, intentional contamination by anyone, including police officers and other including police officers and other official personnelofficial personnel

s.129 of the Code, obstructing a s.129 of the Code, obstructing a police officer in the lawful execution police officer in the lawful execution of his/her duties; gives police of his/her duties; gives police authority to cordon off and refuse authority to cordon off and refuse entry to a crime sceneentry to a crime scene


Officer in charge of investigation Officer in charge of investigation determines when crime scene may determines when crime scene may be safely returned to public accessbe safely returned to public access


Security of the scene falls under the Security of the scene falls under the coroner’s authority in the following coroner’s authority in the following cases:cases: Sudden or unexpected deathsSudden or unexpected deaths Deaths of person in custodyDeaths of person in custody Deaths occurring in institutions, agedDeaths occurring in institutions, aged Deaths from violenceDeaths from violence SuicidesSuicides Deaths occurring in a suspicious, Deaths occurring in a suspicious,

unusual, or unnatural mannerunusual, or unnatural manner


Police officers may seize anything Police officers may seize anything relevant to the investigation at the relevant to the investigation at the crime scene and to maintain the crime scene and to maintain the security of the scene until it is security of the scene until it is ordered released by the coroner ordered released by the coroner following the post mortem following the post mortem examinationexamination

Processing the Crime SceneProcessing the Crime Scene

Focus of police investigation is the Focus of police investigation is the collection of physical evidencecollection of physical evidence

CSI (“Crime Scene Investigation”) CSI (“Crime Scene Investigation”) carried out by a mobile crime labcarried out by a mobile crime lab

Police prepare a Police prepare a descriptiondescription of what of what they findthey find

Police Police photographphotograph a scene a scene Police prepare Police prepare diagramsdiagrams of sketches of sketches Police collect Police collect evidenceevidence

Crime Scene ProcedureCrime Scene Procedure

Important to safeguard the continuity Important to safeguard the continuity of evidence:of evidence: No exhibit is left unattended from the No exhibit is left unattended from the

time of its seizure until it is deposited in time of its seizure until it is deposited in the police property – stage facilitythe police property – stage facility

The officer who seized the item, or the The officer who seized the item, or the case officer, must secure the evidence case officer, must secure the evidence in the police property locker, which is in the police property locker, which is under the control of the property clerkunder the control of the property clerk

Crime Scene ProcedureCrime Scene Procedure

The transfer of any evidence to the The transfer of any evidence to the forensic laboratory is the responsibility of forensic laboratory is the responsibility of the case officer and/or his or her designatethe case officer and/or his or her designate

The transfer of evidence to and from court The transfer of evidence to and from court is the responsibility of the case officeris the responsibility of the case officer

No exhibit can be removed from the No exhibit can be removed from the control of the property clerk without the control of the property clerk without the appropriate authority and signatureappropriate authority and signature

The case officer is the officer in charge of The case officer is the officer in charge of the investigationthe investigation

Processing Physical EvidenceProcessing Physical Evidence

Forensic scientists job is to put the Forensic scientists job is to put the evidence together correctly like the evidence together correctly like the pieces of a puzzlepieces of a puzzle

Analysis of the evidence may involve Analysis of the evidence may involve biology, chemistry, physics, biology, chemistry, physics, anthropology, geology, and computer anthropology, geology, and computer sciencescience

Often called on to give expert Often called on to give expert testimony in courttestimony in court

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Some Pictures Made with Some Pictures Made with FingerprintsFingerprints

FingerprintsFingerprints

Along with DNA, fingerprints are Along with DNA, fingerprints are considered by many to be the best considered by many to be the best way to identify a suspectway to identify a suspect

Fingerprints never change and are Fingerprints never change and are unique to each personunique to each person

Fingerprint patterns can be identified Fingerprint patterns can be identified as one of three types:as one of three types:


1. 1. ArchesArches, forming ridges that run , forming ridges that run from one side of the print to the from one side of the print to the other and curve up the middleother and curve up the middle

2. 2. LoopsLoops, showing stronger curves , showing stronger curves than arches with ends that start on than arches with ends that start on one side of the finger, loop around, one side of the finger, loop around, and end up in the same placeand end up in the same place

3. 3. WhorlsWhorls, forming complete ovals, , forming complete ovals, often in a spiral pattern around a often in a spiral pattern around a central pointcentral point

Fingerprint PatternsFingerprint Patterns

Latent FingerprintsLatent Fingerprints

Created when a person’s fingers Created when a person’s fingers come into contact with an object come into contact with an object such a piece of glass or of plasticsuch a piece of glass or of plastic

Created by a residue of oil and Created by a residue of oil and perspiration from the fingertipperspiration from the fingertip

Usually invisible and requires the Usually invisible and requires the application of chemicals or laser lightapplication of chemicals or laser light

Visible Impressions or FingerprintsVisible Impressions or Fingerprints

Result of a finger’s contact where Result of a finger’s contact where blood, dust or grease has been blood, dust or grease has been previously depositedpreviously deposited


Moulded fingerprints:Moulded fingerprints: Leaves a visible impression in a soft Leaves a visible impression in a soft

substance such as clay, wax or puttysubstance such as clay, wax or putty

Fingerprints ProcessingFingerprints Processing

Fingerprints taken from crime scene Fingerprints taken from crime scene are sent to a central repository are sent to a central repository administered by the RCMP in Ottawaadministered by the RCMP in Ottawa

If the quality of the fingerprint is If the quality of the fingerprint is adequate (20% of a print) and the adequate (20% of a print) and the individual’s prints are on file as a individual’s prints are on file as a result of previous arrest or conviction result of previous arrest or conviction the individual’s identity can be the individual’s identity can be determined through comparisondetermined through comparison

Fingerprints ProcessingFingerprints Processing

Characteristics of each print are Characteristics of each print are examined by expertsexamined by experts

When there are a sufficient number When there are a sufficient number of characteristics thought to be of characteristics thought to be identical (usually 10 to 12 points of identical (usually 10 to 12 points of comparison) an expert may form the comparison) an expert may form the opinion that the print submitted is opinion that the print submitted is that of the individual whose prints that of the individual whose prints are on fileare on file

Henry System of Fingerprint Henry System of Fingerprint ClassificationClassification

Galton Details, Points of Identity or Galton Details, Points of Identity or MinutiaeMinutiae

Identification by fingerprints relies on pattern Identification by fingerprints relies on pattern matching followed by the detection of certain matching followed by the detection of certain ridge characteristics, also so known as Galton ridge characteristics, also so known as Galton details, points of identity, or minutiae, and the details, points of identity, or minutiae, and the comparison of the relative positions of these comparison of the relative positions of these minutiae points with a reference print, usually minutiae points with a reference print, usually an inked impression of a suspect's print. an inked impression of a suspect's print. There There are three basic ridge characteristics, the ridge are three basic ridge characteristics, the ridge ending, the bifurcation and the dot (or island)ending, the bifurcation and the dot (or island). .

Source: shs.westport.k12.ct.us/…/handoutSource: shs.westport.k12.ct.us/…/handout


Identification points consist of bifurcations, Identification points consist of bifurcations, ending ridges, dots, ridges and islands. A ending ridges, dots, ridges and islands. A single rolled fingerprint may have as many as single rolled fingerprint may have as many as 100 or more identification points that can be 100 or more identification points that can be used for identification purposes. There is no used for identification purposes. There is no exact size requirement as the number of exact size requirement as the number of points found on a fingerprint impression points found on a fingerprint impression depend on the location of the print. As an depend on the location of the print. As an example the area immediately surrounding a example the area immediately surrounding a delta will probably contain more points per delta will probably contain more points per square millimetre than the area near the tip of square millimetre than the area near the tip of the finger which tends to not have that many the finger which tends to not have that many points. points.



DotDot

IslandIsland


BirfurcationBirfurcation


Ending ridgeEnding ridge


Image 1 Image 2


In In image 1image 1 we see part of a fully rolled we see part of a fully rolled fingerprint. Notice that the edges are cut-off fingerprint. Notice that the edges are cut-off so you can safely assume that this is not a so you can safely assume that this is not a fully rolled impression. If you take a look at fully rolled impression. If you take a look at image 2image 2 you can see that the centre portion you can see that the centre portion of this impression has been sectioned out of this impression has been sectioned out and 10 points of identification have been and 10 points of identification have been labelled. That was not all the points found labelled. That was not all the points found but simply the ones that could be mapped but simply the ones that could be mapped easily without cluttering up the image.easily without cluttering up the image.

Primary Classification ActivityPrimary Classification Activity

Fingerprint ActivityFingerprint Activity

You are all going to take your You are all going to take your fingerprints (I will give verbal fingerprints (I will give verbal instructions)instructions)

After we take them, we will use the After we take them, we will use the Henry System of Classification to get Henry System of Classification to get your fingerprint “number”your fingerprint “number”

We will also see if there are any We will also see if there are any identical numbers in the classidentical numbers in the class

Trace ElementsTrace Elements

Includes Includes dirtdirt, , dustdust, , fibresfibres and and residueresidue Origin of these materials may Origin of these materials may

provide a link between a suspect and provide a link between a suspect and a crimea crime

Material at an arson scene may Material at an arson scene may produce trace elements of an produce trace elements of an accelerant used to start or maintain accelerant used to start or maintain a firea fire

Trace ElementsTrace Elements

Further examination may uncover Further examination may uncover the specific chemical composition of the specific chemical composition of the fluid, thus linking it to a suspect the fluid, thus linking it to a suspect who possesses the same materialwho possesses the same material

Transfer of trace elements such as Transfer of trace elements such as hair and fibres between the hair and fibres between the perpetrator and the victim is perpetrator and the victim is common in crimes such as common in crimes such as homicides, aggravated assault and homicides, aggravated assault and kidnapping kidnapping

HairHair

If the sample contains the root, shaft If the sample contains the root, shaft and tip, it may reveal:and tip, it may reveal: a person’s racial backgrounda person’s racial background the area of the body from which the hair the area of the body from which the hair

originatedoriginated the person’s blood typethe person’s blood type

FibresFibres

Examination may determine their Examination may determine their point of origin or manufacturerpoint of origin or manufacturer

Matching the fibres found on the sole Matching the fibres found on the sole of the shoe of a victim with the of the shoe of a victim with the accuser’s residencesaccuser’s residences

BloodBlood

In impaired-driving offences, blood In impaired-driving offences, blood evidence is paramountevidence is paramount

Also relevant in cases where a Also relevant in cases where a suspect’s mens rea is in issue as a suspect’s mens rea is in issue as a result of intoxicating substancesresult of intoxicating substances

Blood is a fluid that conforms to the Blood is a fluid that conforms to the laws governing the motion and laws governing the motion and properties of other fluidsproperties of other fluids

BloodBlood

Study the size and shape of blood Study the size and shape of blood drops on a floor can indicate the drops on a floor can indicate the height from which they fell and thus height from which they fell and thus the location of the woundthe location of the wound

Shape may indicate movement; a Shape may indicate movement; a person in motion while bleeding person in motion while bleeding produces a tear-shape drop, with the produces a tear-shape drop, with the narrow end indicating the direction of narrow end indicating the direction of travel and the rounded end pointing travel and the rounded end pointing towards the bleedertowards the bleeder

BloodBlood

Blood splatter patterns on the wall Blood splatter patterns on the wall may indicate the force and direction may indicate the force and direction of a blow and indicate how far the of a blow and indicate how far the victim was from the wall when the victim was from the wall when the wound was inflictedwound was inflicted

Gunshot ResidueGunshot Residue Includes:Includes:

GasesGases Unburned or partially burned power grainsUnburned or partially burned power grains Carbon particlesCarbon particles Trace of the bullet lubricantTrace of the bullet lubricant Traces of primer components (lead, Traces of primer components (lead,

barium, nitrates)barium, nitrates) Fragments of soft bullets (lead antimony)Fragments of soft bullets (lead antimony) Fragments of the bullet jacketFragments of the bullet jacket Metal traces for the cartridge case or gun Metal traces for the cartridge case or gun

barrelbarrel

Gunshot ResidueGunshot Residue

These trace elements are deposited These trace elements are deposited on the hands of the person on the hands of the person discharging the gundischarging the gun

Under circumstances, detectable and Under circumstances, detectable and identifiableidentifiable

Gunshot Residue – Hand Wash Gunshot Residue – Hand Wash TestTest

Requires the suspect to wash his or Requires the suspect to wash his or her hands in a chemical solutionher hands in a chemical solution

Solution is then sent to the Solution is then sent to the laboratory for analysislaboratory for analysis

Test can detect elevated levels of Test can detect elevated levels of lead, barium, and antimonylead, barium, and antimony

May indicate that the suspect has May indicate that the suspect has fired a gun recentlyfired a gun recently

Gunshot ResidueGunshot Residue

GSR test cannot determine the time GSR test cannot determine the time at which the suspect may have fired at which the suspect may have fired the gunthe gun

It is less effective when the time It is less effective when the time between firing the fun and taking the between firing the fun and taking the hand wash exceeds four hourshand wash exceeds four hours

Gunshot Residue – Scanning Gunshot Residue – Scanning Electron Microscopy SEMElectron Microscopy SEM

Provides results that appear to be Provides results that appear to be more accurate and consistent than more accurate and consistent than the hand wash testthe hand wash test

Special utensil containing a gummed Special utensil containing a gummed substance is held against the skin substance is held against the skin and them removedand them removed

GSR adheres to the gummed GSR adheres to the gummed substance, which is then prepared substance, which is then prepared for examination by the scanning for examination by the scanning electron microscopeelectron microscope

DNA: Deoxyribonucleic AcidDNA: Deoxyribonucleic Acid

All human beings have a distinctive All human beings have a distinctive genetic code within their 46 genetic code within their 46 chromosomeschromosomes

Identification of an individual through Identification of an individual through his or her distinctive genetic codehis or her distinctive genetic code


Minute samples of:Minute samples of: Blood including a blood stainBlood including a blood stain SemenSemen SalivaSaliva Vaginal secretionsVaginal secretions SkinSkin Hair folliclesHair follicles

Can be used…Can be used…


Are sufficient to produce reliable results Are sufficient to produce reliable results even when the sample combines two or even when the sample combines two or more substancesmore substances

This contamination does not affect the This contamination does not affect the reliability of the testreliability of the test

Properly analyzed, it can identify an Properly analyzed, it can identify an individual with a certainty exceeding one individual with a certainty exceeding one in several billionin several billion

Has also been used to rule out suspects, or Has also been used to rule out suspects, or to overturn wrongful convictionsto overturn wrongful convictions

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Documents

Chapter 8 – Crime and Criminal Law Unit 3 – Criminal Law Crime Scene Investigation