Metals
Name two common forms of metal trace evidence found at a crime scene.
What are bullet fragments and metal shavings?
What does GSR stand for?
What is Gunshot Residue
Give two examples of partial impressions useful to investigators besides fingerprints.
What are ear prints and glove impressions?
Why is paint valuable trace evidence in hit-and-run cases?
What is paint transfer can link a vehicle to a victim, object, or crime scene, and may help narrow vehicle identification?
Give one safe practice for preventing contamination when collecting trace evidence.
What is wearing clean gloves and changing them between evidence items?
Which instrument provides elemental identification by detecting X-ray emissions from a sample's surface?
What is Energy Dispersive X-ray Spectroscopy (EDS)?
Name two types of powders, other than GSR, important in forensic investigations and give one investigative value for each.
What are drug residues, which may indicate controlled substance activity, and industrial powders, which may link evidence to a workplace or manufacturing source?
What is cheiloscopy?
What is the study and analysis of lip prints?
What is the Paint Data Query (PDQ) database used for?
What is comparing automotive paint characteristics to help narrow possible vehicle make, model, and year ranges?
Name two sampling methods appropriate for trace evidence and give an example for each.
What are:
Explain briefly how tool marks can link a suspect to a crime.
Tool marks can contain unique microscopic striations and patterns that may be compared to a suspect's tool to associate it with the crime scene.
Outline a multi-step approach for analyzing an unknown powder found at a crime scene.
What is:
Name two enhancement methods for latent smudges or partial fingerprints and what each reacts with or uses.
What are:
Name one collection technique?
What is tape lifting?
Why are paper containers preferred for certain types of evidence?
What is paper allows moisture to escape and reduces mold growth; for example, biological-stained clothing may be packaged in paper?
Which technique determines trace elemental concentrations with very high sensitivity and is often used for metal residue analysis?
What is Inductively Coupled Plasma Mass Spectrometry (ICP-MS)?
Name a lab technique that gives a molecular "fingerprint" of a powder by measuring infrared absorption.
What is FTIR (Fourier Transform Infrared Spectroscopy)?
Compare the evidentiary strength and limitations of ear and lip prints with fingerprint evidence.
Ear and lip prints can provide corroborative evidence but are generally less standardized and have less database and validation support than fingerprint evidence.
Name three paint characteristics analysts examine to link a paint chip to a source.
What are color/layer sequence, pigment composition, and binder composition?
Provide a protocol for collecting and preserving a small trace item, like a paint chip.
What is:
A hit-and-run yields paint containing unique metal particles. What database or combined analytical approach could help identify the vehicle make/model?
What is Paint Data Query (PDQ) database.
Name a lab technique that gives a molecular "fingerprint" of a powder by measuring infrared absorption.
What is FTIR (Fourier Transform Infrared Spectroscopy)?
Give at least three lip-print pattern types.
What are vertical, branched, intersected, and reticular patterns?
Explain how sequence-of-layers analysis helps determine the origin of a paint chip.
What is comparing the order and characteristics of layers such as primer, basecoat, and clearcoat to known samples to help associate the chip with a possible source?
Name three key elements that should appear on an evidence label or chain-of-custody form.
What are case number, item description, recovery location, date/time collected, and collector identification?