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CSI
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Crime Scene Investigation CSI
By: Dr/ Marwa Magdy Demonstrator of forensic medicine & toxicology
Expectations
Objectives
• Vocabulary• principles of crime scene investigation• Stages of CSISecuring SearchingDocumentingCollecting & preserving trace evidence
Crime scene: Any physical location in which a crime or accident has occurred suspected of having occurred.
Source: http://www3.sc.maricopa.edu/ajs/crime_scene_technician.htm
Physical evidence: any material items that would be present at the crime scene, on the victim, or found in a suspect’s possession.
Trace evidence: physical evidence present at the crime scene in small but measurable amounts.
Suspect: person thought to be capable of comitting a crime.
Vocabulary
1) Time frame
2) Crime scene zone
3) Crime scene investigation team
4) Crime scene investigation equipment
5) Crime scene search patterns
Source: http://www3.sc.maricopa.edu/ajs/crime_scene_technician.htm
Principles of CSI
Time frame• Arrival of the CSI team should be as soon as
possible since the crime was reported.
• Late arrival at the crime scene may result in loosing important evidence.
Crime scene zone
• Boundaries of the crime scene → as far as signs of committing a crime are visible.
Boundaries are defined by the head of the CSI team.
• Assailant’s path of entry andexite.g: windows,doors.
CSI Team
• Head of the crime scene investiagtion team “prosecutor” . النيابة وكيل
• Forensic pathologist الشرعى الطبيب• police officer (investigator)المحقق • Photographer الجنائى المصور• Latent prints expert البصمات خبير• Explosives expert المفرقعات خبير• Members of CSI team الجنائى البحث فريق أعضاء
CSI equipments• equipment for securing and preserving the crime
scene• equipment for collecting and packaging of evidence
• equipment for recording the crime scene and evidence.
Tools for evidence collection• Rubber gloves.• Strong flashlight.• Syringes & needles.• Forceps & scissors .• Hand lens.• Labels & containers.• Plastic vials & jars.• Paper bags.
Searching the crime scene
Stages of CSI
1. Securing the crime scene2. Searching the crime scene3. Documenting & photographing4. Collecting & preserving evidence
Securing the scene• Defining boundaries of the crime scene
• Entry is prohibited
• Every person who enters the crime scene has the potential to destroy physical evidence.
• Ensuring security for the crime scene investigation team members
• CSI team should wear protective clothes.
CSI video 2.flv
Searching the scene
Crime scene search patterns
• Many distinctive methods of searching the
crime scene.
• For different types of crimes, different search
patterns are suggested.
Searching the crime scene
Documenting the scene
• 3 methods of crime-scene recording:
• Photography • Sketches • Notes
• Ideally all 3 should be used.
Photography • At this stage touching or moving objects is
prohibitted
• Particularly cadavers SHOULD remain untouched
• Objects may be marked with numbers and photographed
• what ?Crime scene & adjacent areasEntry & exitCadaver , weapon & injuries
Pictures can tell …
sketches
Collecting & preserving evidence
• Common types of trace evidenceBloodSemenSalivaFingerprintsHairsFibersExplosivesWeapons
Glass ImpressionsPaintPetroleum productsPlastic bagsPowder residueSoil and mineralsTool marksWood
Why is trace evidence useful?
Blood stain
Finding The Stains:
Reagents :“Luminol and fluorescein” can reveal blood that has been watered down to a ratio of 12000:1.
Seminal stain
• Seminal stains on dark material often have a white glistening appearance.
• Preliminary test (Ultraviolet light): bluish white fluorescence.
• Confirmatory test (Microscopic detection of spermatozoa)
• DNA of assailant
Saliva stains
• Could be detected anywhere on clothing,bites,enveloppe& cigarette bits.
• DNA of the assailant
Hair Human or animal Race Origin Manner in which hair
was removed Drugs ingested DNA analysis
Latent prints
• Types :FingerprintPalmSole LipEarFoottyre
Latent prints