Evidence Collection and Preservation Flashcards

What is the first step in securing a crime scene?

Answer: Restrict unauthorized access

The absolute first step in securing a crime scene is to establish a perimeter and restrict access to authorized personnel only. This prevents contamination, destruction, or alteration of evidence by unauthorized individuals. Maintaining the integrity of the scene is paramount for a successful and credible investigation.

Which type of evidence is considered the most fragile and should be collected first?

Answer: Biological evidence (blood, hair, fibers)

Biological evidence, such as blood, hair, and fibers, is highly susceptible to degradation, contamination, and loss due to environmental factors or accidental destruction. It must be collected first to ensure its preservation for forensic analysis. Prioritizing the collection of such fragile evidence is crucial for maintaining its integrity and evidentiary value.

Why is it important to document the chain of custody for evidence?

Answer: To prevent evidence tampering and maintain credibility

The chain of custody is a meticulous record of every person who has handled a piece of evidence from its collection to its presentation in court. Documenting this chain ensures that the evidence has not been tampered with, altered, or substituted, thereby maintaining its integrity and admissibility in legal proceedings. It establishes the authenticity and reliability of the evidence.

What is the recommended method for collecting fingerprint evidence?

Answer: Using fingerprint powder and lifting tape

For visible or latent fingerprints on non-porous surfaces, the standard method involves applying fine powder to adhere to the oils and sweat left by the finger. Once the print is visible, it is then carefully lifted using adhesive tape and transferred to a contrasting surface for preservation and analysis. This technique effectively captures the unique ridge patterns for identification.

Which type of evidence should be stored in a breathable container to prevent degradation?

Answer: Biological evidence (bloodstained clothing)

Biological evidence, especially items like bloodstained clothing, must be stored in breathable containers such as paper bags or cardboard boxes. This prevents the accumulation of moisture, which can promote mold growth and bacterial degradation, thereby preserving the integrity of DNA and other biological materials. Plastic bags can trap moisture and ruin such evidence.

Why is it important to take photographs of the crime scene before collecting evidence?

Answer: To document evidence location and crime scene condition

Photographs provide a permanent visual record of the crime scene's original state before any evidence is moved or collected. They document the precise location of evidence, the overall layout, and the condition of the scene, which is crucial for reconstruction and later analysis. This initial documentation is vital for maintaining the context and integrity of the evidence.