CRIME SCENE INVESTIGATION

BYAKANYA M. AUGUSTINE

BEING A PRESENTATION DURING A STEP DOWN TRAINING TITLED SEX CRIMES AND CRIME SCENE INVESTIGATION, AT THE EFCC ACADEMY, KARUON 6TH 7TH AUGUST, 2014

EXPECTED OUTCOMESAt the end of this presentation, participants will be able toIdentify, preserve, collect, process and properly document physical evidence.

CRIME SCENE:Location where crime was committedPrimarySecondaryDuty of Crime Scene Investigator:Examination and evaluation of a Scene to recover physical evidence and its context.Physical Evidence: Any object that can prove or disprove material fact.

PHYSICAL EVIDENCE: ANY OBJECT THAT CAN PROVE OR DISPROVE MATERIAL FACT.ObjectiveSpeaks for itselfDoes not lieNot subject to human emotions

Purposes of Physical Evidence: To establish the elements of a crimeCorroborationReconstructionInvestigation leadsInvestigative Linkage

Crime Scene

Suspect Victim

Common physical Evidence:ImpressionsLatent Print ImpressionsTrace materials

COMMON PHYSICAL EVIDENCE:BiologicalBallisticQuestioned documentsDigitalChemical

CRIME SCENE MANAGEMENTContact first ResponderAccess Scene SecurityCrime scene preservationSecure Large perimeterIdentify entry and exit pointsSecure peopleConduct preliminary interview of witnesses (victims, witnesses and suspects)Gather as much information as possible before walk throughEvidence recognition and identification (use markers)Access forensic and equipment needs

CRIME SCENE PHOTOGRAPHYProvides a fair and accurate visual depiction of the crime scene and associated physical evidence.Generally the most effective method of documentation.CAMERA:Check batteryInstall Media cardFocus control (automatic A or or manual M)Activate camera flash

FORENSIC PHOTOGRAPHYShow context of evidenceExamination QualityMaximum detail of forensic evidence

Examination Quality Images:Latent print evidence (finger, palm and bare foot impressions)Footwear impressionsTire impressionsBite MarksBlood stain patterns

STEPS IN EXAMINATION QUALITY IMAGESCloseup lens90 degrees perspectiveStabilize camera (use tripod if available)Place marked scale adjacent to evidenceManually focusSet continuous lighting sourceCapture Image with lighting in place

LIGHTING:Front Lighting May cause reflection problemsOblique lighting Avoids reflection, visualizes texture better.

NOTES:Format memory cardDo not delete imagesBackup image file

TRACE AND BIOLOGICAL EVIDENCEVery broad definitionTransferred through interchange and can be traced back to sourceIncludes many types of small and microscopic items

Principle of Interchange: It is highly improbable that someone can enter an environment and leave that environment without leaving something of themselves or taking something of the environment with them. Dr. Edmund Locard

COMMON TYPES OF TRACE EVIDENCEHairs (Human and Animal)Fibers (Natural and Synthetic fiber)PaintGlassBiological evidenceSoilsGun powder residueOthers

BIOLOGICAL EVIDENCE: MATERIALS AND FLUIDS SECRETED FROM THE HUMAN BODY. Types of Biological evidence:BloodSemen UrineSalivaTouch DNAVaginal secretionsOthers

LATENT PRINT IMPRESSION EVIDENCE:These are objects or materials that have retained the characteristics of other objects or materials through direct physical contact.Friction Ridge SkinMedium of transfer: Natural oils Contaminants: Foreign oils, greases etcInk, blood, others

METHODOLOGYSearchDevelopPreserve

Physical Development (Powders) Types:Conventional PowdersMagnetic PowdersPowders may be white, Black, fluorescent or Biochromatic

STEPS:Avoid dipping brush into JarApply powder to brush tips onlyLightly brush surface until ridges appearAdd powder to attain contrast

PRESERVATION OF LATENT PRINTS PhotographyCapture context photosCapture content (Examination Quality) Lift Powder ImpressionsTape liftingRubber gelatinCasting Bag and Tag

EXERCISE 1 State True or False:Contaminant is a medium of transfer for Latent Impressions.Front lighting is preferable for Examination quality images.Powders are used for physical development of Latent impressions.Physical evidence is not subject to human emotionsSoil is not a trace evidence

PRACTICAL EXERCISE 2Using the methods taught during this training, You are to Search and develop the latent Print impression on the crime scene.