Crime Scene Processing Flashcards

The 'Locard Exchange Principle' is most directly relevant to crime scene processing because it states that:

Answer: When two objects contact each other, trace material is exchanged

Locard's principle holds that every contact between a person and a scene results in the transfer of trace material in both directions.

A technician is casting a tire track in soft soil. Which material is most commonly used?

Answer: Dental stone (die stone)

Dental stone is preferred over plaster of Paris for tire and shoe impression casting because it is harder, more durable, and captures finer detail.

Which action would MOST compromise the integrity of digital evidence found on a computer at a crime scene?

Answer: Powering on the computer to check its contents

Powering on a computer can alter timestamps, overwrite temporary files, and activate encryption, destroying critical digital evidence.

At an outdoor homicide scene, what environmental factor poses the greatest threat to trace DNA evidence?

Answer: UV radiation and moisture

UV radiation breaks down DNA strands and moisture accelerates microbial degradation, making them the primary environmental threats to trace DNA.

When should a crime scene log (scene entry/exit record) be initiated?

Answer: Immediately upon securing the scene

The scene log must begin as soon as the scene is secured to record every person who enters or exits from that point forward.

A bloodstain with a circular shape and smooth edges most likely indicates the blood fell at approximately what angle?

Answer: 90 degrees (perpendicular)

Blood falling at 90 degrees to a surface produces a circular stain with smooth, even edges because there is no angular distortion.

Which step is performed LAST when processing a latent fingerprint with cyanoacrylate (super glue) fuming?

Answer: Photographing the developed prints

After cyanoacrylate fuming develops the print and optional dye staining enhances contrast, the final step is photography to document the result.