ETC ETC Fingerprint & Biometric Evidence 2 — Questions and Answers
Question 1: Which fingerprint development technique is most appropriate for latent prints on wet evidence?
- Small particle reagent (SPR) (Correct answer)
- Ninhydrin
- Cyanoacrylate fuming
- Standard carbon powder
Correct answer: Small particle reagent (SPR)
Small particle reagent (SPR) is a suspension of molybdenum disulfide that adheres to fatty components of latent prints even on wet surfaces.
Question 2: What is the ACE-V methodology used in latent print examination?
- Analysis, Comparison, Evaluation, and Verification — the scientific method for fingerprint examination (Correct answer)
- Acquire, Capture, Enhance, and Verify — the digital imaging process
- Authenticate, Classify, Extract, and Validate — the AFIS search process
- Archive, Catalog, Examine, and Version — the evidence logging system
Correct answer: Analysis, Comparison, Evaluation, and Verification — the scientific method for fingerprint examination
ACE-V (Analysis, Comparison, Evaluation, Verification) is the standardized scientific methodology used by latent print examiners to reach identification conclusions.
Question 3: An evidence technician finds a bloody print at a scene. Which technique should be used to enhance it?
- Amido black or leuco crystal violet staining (Correct answer)
- Cyanoacrylate fuming
- Standard fingerprint powder
- Ninhydrin application
Correct answer: Amido black or leuco crystal violet staining
Amido black and leuco crystal violet react with proteins in blood to intensify and enhance bloody prints for photography and comparison.
Question 4: What is the primary difference between a patent print and a latent print?
- A patent print is visible to the naked eye; a latent print requires development to be seen (Correct answer)
- A patent print is left on paper; a latent print is left on glass
- A patent print is three-dimensional; a latent print is two-dimensional
- A patent print is from a toe; a latent print is from a finger
Correct answer: A patent print is visible to the naked eye; a latent print requires development to be seen
Patent prints are visible without enhancement (e.g., prints in blood or grease), while latent prints are invisible and require development techniques to visualize.
Question 5: How many points of comparison are required by US federal standards to declare a fingerprint identification?
- There is no mandated minimum — examiners use a holistic sufficiency standard (Correct answer)
- A minimum of 12 points is federally mandated
- A minimum of 8 points is federally mandated
- A minimum of 16 points is federally mandated
Correct answer: There is no mandated minimum — examiners use a holistic sufficiency standard
The FBI and most US agencies follow a sufficiency standard rather than a fixed point minimum; the examiner must find sufficient unique features without unexplained differences.
Question 6: Which alternate light source wavelength range is commonly used to visualize fluorescent fingerprint powders?
- Blue-green light (450–530 nm) with orange or yellow goggles (Correct answer)
- Red light (600–700 nm) with green goggles
- UV light at 254 nm with no goggles
- Infrared light (900 nm) with standard glasses
Correct answer: Blue-green light (450–530 nm) with orange or yellow goggles
Fluorescent powders are typically excited by blue-green light (around 450–530 nm), and barrier goggles in the orange or yellow range block the excitation wavelength so only the fluorescence is visible.
ETC ETC Fingerprint & Biometric Evidence 2
Which fingerprint development technique is most appropriate for latent prints on wet evidence?