Crime Scene Processing

Detective Gerry Durand (ret.)

Disclaimer

The photographs you are about to see are actual crime scene photographs. These photos and the accompanying discussions are very graphic and may be disturbing to some people. To respect the privacy of the victims, actual addresses and some details have been changed.

Functions of BCI Division Processing of Crime Scene Processing of Prisoners Registering Sex Offenders Miscellaneous Duties

ID’s Fingerprinting for firearms and Child Care Background checks for employment

Processing of Prisoners Demographics

name, sex, height, weight, employment Fingerprints Mug Shot

Forensics the application of science to matters of law Physical Evidence

Anything that tends to establish or disprove a fact

Processing Crime Scene Document Scene

Notes Photography Video Diagram

Collection of Evidence Fingerprints Specific Tasks

Blood Spatter Bullet Trajectory

Notes Chronological Order Step by step Complete and thorough Legibly Negative or unexpected conditions Be as specific as possible

Crime Scene Search Survey the scene Photographing and sketching

Measuring evidence Locard’s Theory

Every contact leaves a trace Anytime someone or something enters a crime

scene, they alter it in some way (depositing or removing evidence)

Search Patterns 4 types

Quadrant (indoor) Grid (outdoor) Strip or line (large # of personnel) Spiral (alone)

Diagramming Shows a two-dimensional picture of a

three-dimensional scene Eliminates extraneous items that have

limited evidentiary value

Diagramming Reference Point *absolutely needed*

An engineered object (measured and recorded)

Building Manhole Cover/fire hydrant Road/ curbing Telephone pole Large Tree/Rock

What if there is no point

Diagramming Measuring

Baseline Triangulation

Sketching Final Sketch

Needed on the sketch Reference Point Orientation Case Information

Case number Name of suspect/victim/investigator/author Date/time

Scale Legend

N->

Photographing the scene Point of entry All corners of the room ceiling

Photography 35mm vs. Digital

35mm Actual Negative

(harder to change) Jury is familiar with it Familiar Camera Permanent record

(hard drive crashes)

Digital Quick turn-around

time Easy to change

lighting, contrast Don’t have to worry

about developing sensitive photos

Video Real-time Moves around objects Zoom and wide angle Quick

Blair witch effect Sound

Seizing Evidence Pitfalls

Documentation chain of custody contaminating evidence

Trace Evidence

Blood (Luminol) Semen Hairs and Fibers Saliva Fingerprints

Alternate Light Source uses different

wavelengths of visible light to “fluoresce” items for easier viewing

objects or substances contacting one another, and leaving a minute sample on the contact surfaces

Order of Tasks at a Crime Scene Aid to Victim Search for additional victims and suspects Separate Witnesses Establish a perimeter Do NOT allow victims or suspects back in

the crime scene

What can be touched at the Crime Scene

NOTHING