Trace Evidence and Crime Scene Reconstruction (Hair, Fibre, Glass, Paint, GSR) MCQs

Forensic Medicine · 18 free questions with answers & explanations.

1. Gunshot residue (GSR) analysis by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) identifies characteristic particles containing which triad of elements?
2. In forensic hair examination using light microscopy, which feature MOST reliably distinguishes human head hair from animal (canine) hair?
3. Bloodstain pattern analysis (BPA) at a crime scene shows multiple elliptical blood drops with gamma (tail/satellite) angles pointing toward the doorway. This indicates the direction of blood travel was:
4. Glass fracture pattern analysis at a crime scene reveals radial cracks with hackle marks. The rib marks on the radial fractures are perpendicular to the glass surface on the OPPOSITE side from the impact. This follows which principle?
5. A forensic examiner examines a single hair recovered from a crime scene and wishes to determine whether it is human or animal, and whether it was shed naturally or forcibly removed. The MOST appropriate technique combining morphology and molecular analysis is:
6. Gunshot residue (GSR) particles are characterised by the presence of which elemental triad detected by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX)?
7. In forensic glass analysis, the most discriminating physical property used to compare glass fragments from a crime scene and suspect is:
8. Locard's exchange principle is the theoretical foundation for trace evidence collection. It states that:
9. Gunshot residue (GSR) analysis by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) is considered positive when particles containing which elemental combination are found?
10. Locard's exchange principle underpins trace evidence analysis. In a murder case, the victim's jumper contains blue nylon fibres matching the suspect's car seat cover. The significance of this single fibre transfer is BEST interpreted as:
11. In forensic hair analysis, which microscopic feature can distinguish human hair from animal hair?
12. A forensic scientist examines broken glass fragments from a hit-and-run scene. Refractive index (RI) measurement by the oil immersion method shows the crime scene glass has an RI of 1.5230 ± 0.0002 and the suspect vehicle's headlight glass measures 1.5228 ± 0.0002. The MOST appropriate interpretation is:
13. At a shooting scene, gunshot residue (GSR) is collected from a suspect's hands. The definitive analytical method for GSR confirmation and the characteristic tri-elemental particle composition sought is:
14. In forensic hair examination, mitochondrial DNA analysis is preferred over nuclear DNA for telogen phase hair shafts. The microscopic feature that BEST distinguishes human hair from dog hair is:
15. Fracture pattern analysis of glass found at a crime scene can indicate direction of impact. The distinguishing feature between radial and concentric fractures in terms of rib mark orientation is:
16. At an autopsy, a criminalist collects a hair from the victim's clothing. Microscopic examination reveals: medullary index > 0.5, continuous amorphous medulla, absence of cortical fusi, and scales with a mosaic pattern. This hair is MOST likely from:
17. Gunshot residue (GSR) analysis using Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX) detects characteristic particles. What is the SPECIFIC elemental composition of a 'unique' GSR particle that unequivocally confirms firing a weapon (conventional lead-based primer)?
18. Glass fracture analysis at a crime scene reveals both radial fractures (extending outward from the impact point) and concentric fractures (rings around the point of impact). In assessing direction of force and sequence of shots in multiple impacts, which principle is applied?