CSI Evidence Collection and Preservation — Questions and Answers
Question 1: What is the first step in securing a crime scene?
- Restrict unauthorized access (Correct answer)
- Start collecting evidence immediately
- Take photographs of the scene
- Call forensic experts to the scene
Correct 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.
Question 2: Which type of evidence is considered the most fragile and should be collected first?
- Biological evidence (blood, hair, fibers) (Correct answer)
- Firearms and weapons
- Digital evidence from computers
- Vehicle tire impressions
Correct 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.
Question 3: Why is it important to document the chain of custody for evidence?
- To prevent evidence tampering and maintain credibility (Correct answer)
- To avoid duplicate evidence collection
- To speed up forensic analysis
- To limit the number of people accessing the crime scene
Correct 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.
Question 4: What is the recommended method for collecting fingerprint evidence?
- Using fingerprint powder and lifting tape (Correct answer)
- Swabbing with a cotton pad
- Placing fingerprints in a plastic bag
- Photographing fingerprints only
Correct 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.
Question 5: Which type of evidence should be stored in a breathable container to prevent degradation?
- Biological evidence (bloodstained clothing) (Correct answer)
- Metal weapons
- Cell phones and digital evidence
- Drug samples
Correct 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.
Question 6: Why is it important to take photographs of the crime scene before collecting evidence?
- To document evidence location and crime scene condition (Correct answer)
- To speed up evidence collection
- To identify suspects immediately
- To avoid contamination of evidence
Correct 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.
CSI Evidence Collection and Preservation
What is the first step in securing a crime scene?