How to Process the Crime Scene

1) Secure and Isolate: Responsibility of the first officer arriving at the scene. Everyone who is not directly associated is excluded otherwise much of the physical evidence will be destroyed

2) Evaluate Determine if anyone needs medical assistance. Determine the boundaries of the scene Establish the perpetrator’s path of entry and exit.

3) Record the Scene Notes, sketching, photography, and sometimes videotape. These may be presented at trials.

Photography should include: Overview or panoramic of surrounding area Points of exit and entry If indoors, each wall area should be shown If there is a body, photos should show its position, injuries and any weapons near by The surface beneath the body All items of physical evidence including close-ups (using ruler to show size), medium and far views. **If any items are moved, added or have changed position photograph may not be admissible as evidence**.

Sketching Sketching is done after the photographs are taken. A rough sketch is done first Objects are located by distance measurements from two fixed points. Evidence is given letter designations A legend is included below the sketch A compass designating north is shown A finished sketch contains all of the information in the rough sketch. It is drawn with presentation in mind. Sometimes CAD is used

Rough Sketch

Finished Sketch

Measurements Measurements are very critical Every item measured from two reference points Triangulation is most accurate but requires a minimum of two people 90 degree method used for indoor crime scenes-Items measured at a 90° angle to two immovable objects (preferably walls) http://www.authentegrity.com/download/Crime_Scene_Diagramming.pdf

Notes include: A detailed description of the scene The location of items of physical evidence recovered The time the physical evidence was discovered, by whom, how and by whom it was packaged and marked. Other noteworthy sights, sounds, smells, etc.

Conducting a search Must be thorough and systematic Overlooked evidence can lead to accusations of a cover-up attempt Must include all probable points of entry and exit What to search for is determined by the type of crime, for example in a homicide the focus will be on a search for the weapon; a burglary: tool marks at the point of entry In most cases a search for latent fingerprints is required Careful vehicle searches are also done

Crime scene search patterns

Physical evidence Can be massive objects or microscopic traces Possible carriers of trace evidence also collected Clothing collected and wrapped separately Key areas are vacuumed and sweepings submitted (special filter attachments are used )

Physical Evidence From the Deceased Victim: Tissues and organs are retained for pathological and toxicological examination Victims clothing, fingernail scrapings, head and pubic hairs, blood, vaginal, anal and oral swabs (in sex-related crimes), recovered bullets, hand swabs from shooting victims (for gunshot residue), are collected from the body.

Chain of Custody Items are carefully marked and packaged at the scene The collector’s initials and date are inscribed directly in the item or it is tagged Initials, location and date are the minimum requirements. All those involved in the collection and transportation of the evidence must maintain a written record of when and who they received it from and gave it to

Obtaining controls A control or reference is a known standard used for comparison May be obtained from a victim, a suspect, or other source. Ex. Bloodstained evidence must be accompanied by blood samples from all relevant crime scene participants. Each item is packaged separately and assigned a number or letter

Crime scene safety Blood, body fluids and syringes can transmit AIDS or hepatitis B All officers required to be vaccinated against hepatitis B Gloves and Tyvek shoe covers used Sometimes coveralls used Face shield, goggles, or mask used when dust or mist is encountered Red Biohazard bags used for wet blood, and for disposable waste such as clothing, paper, masks etc. Non disposable waste put in yellow plastic bags labeled “Infectious Linen” Eating, drinking, smoking and applying make-up are prohibited!!