CSI Forensic Analysis Techniques 3 — Questions and Answers
Question 1: In bloodstain pattern analysis, what does a 'void pattern' indicate?
- An object blocked blood from reaching a surface (Correct answer)
- Blood was wiped away after deposition
- The victim moved after being struck
- Arterial spurt created a gap in the pattern
Correct answer: An object blocked blood from reaching a surface
A void pattern is an absence of bloodstain in an otherwise continuous pattern, indicating an object or person was present and blocked the blood.
Question 2: Which reagent is commonly used to enhance latent fingerprints on porous surfaces such as paper?
- Ninhydrin (Correct answer)
- Cyanoacrylate fuming
- Luminol
- Amido Black
Correct answer: Ninhydrin
Ninhydrin reacts with amino acids in sweat residue on porous surfaces, producing a purple-colored compound called Ruhemann's purple.
Question 3: What does the term 'skeletonization' refer to in the context of decomposition and forensic entomology?
- Complete removal of soft tissue leaving only bone (Correct answer)
- The pattern left by insect activity on bone
- Early stage mummification of remains
- Loss of bone density post-mortem
Correct answer: Complete removal of soft tissue leaving only bone
Skeletonization refers to the complete removal of soft tissue from a body, exposing the skeletal remains.
Question 4: In forensic serology, what is the ABO blood typing system used to determine?
- Antigens present on red blood cell surfaces (Correct answer)
- DNA profile of the blood donor
- Approximate age of a bloodstain
- Presence of pathogens in the sample
Correct answer: Antigens present on red blood cell surfaces
ABO blood typing identifies specific antigens (A, B, both, or neither) present on the surface of red blood cells.
Question 5: Which technique is used to determine the elemental composition of a glass fragment?
- Energy-dispersive X-ray spectroscopy (EDS) (Correct answer)
- Nuclear magnetic resonance (NMR)
- High-performance liquid chromatography (HPLC)
- Infrared spectroscopy (IR)
Correct answer: Energy-dispersive X-ray spectroscopy (EDS)
EDS analyzes X-rays emitted from a sample when excited by an electron beam, revealing its elemental composition.
Question 6: What is 'substrate control' in trace evidence analysis?
- An unstained portion of the evidence surface tested alongside the sample (Correct answer)
- The medium used to transport trace evidence
- A controlled environment for evidence storage
- The reference database for fiber comparisons
Correct answer: An unstained portion of the evidence surface tested alongside the sample
A substrate control is a sample taken from an unstained area of the evidence surface to account for background contamination.
Question 7: In forensic document examination, what is 'indented writing'?
- Writing impressions transferred to underlying pages when writing on a pad (Correct answer)
- Forgery detected through UV examination
- Erasure marks left on a document
- Ink that penetrates paper fibers deeply
Correct answer: Writing impressions transferred to underlying pages when writing on a pad
Indented writing refers to impressions left on lower sheets when someone writes on a pad, recoverable using electrostatic detection apparatus (ESDA).
CSI Forensic Analysis Techniques 3
In bloodstain pattern analysis, what does a 'void pattern' indicate?