Impression and Pattern Evidence Flashcards
7 cards from real CSI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Impression and Pattern Evidence flashcards as text
What is the 'area of origin' in bloodstain pattern analysis?
Answer: The three-dimensional point in space from which blood was projected
The area of origin is the three-dimensional point in space from which blood droplets were cast, determined by stringing or trigonometric back-calculation of multiple stains.
Which characteristic makes a footwear impression an 'individual characteristic'?
Answer: Unique cuts, gouges, or wear patterns acquired during use
Individual characteristics are random, accidental features such as cuts, nicks, or wear that develop over time and are unique to one specific shoe.
A high-velocity impact spatter at a shooting scene typically produces droplets of what size?
Answer: Less than 1 mm in diameter
High-velocity impacts (such as gunshots) produce very fine mist-like droplets generally less than 1 mm in diameter.
In the examination of questioned documents with indented writing, which instrument is commonly used?
Answer: Electrostatic detection apparatus (ESDA)
The ESDA uses electrostatic charge to visualize pressure indentations left in paper from writing on overlying sheets.
What does the 'point of convergence' tell investigators in blood spatter analysis?
Answer: The two-dimensional location on the floor or wall where the blood originated
The point of convergence is found by extending lines through the long axes of multiple stains; their intersection marks the 2D location of the blood source on that surface.
Which reagent is most commonly used to enhance and photograph bloody shoe prints on dark or patterned surfaces?
Answer: Amido Black
Amido Black is a protein stain that intensifies bloody footwear impressions, making them visible against difficult backgrounds.
A cast recovered from a bite mark on cheese at a burglary scene would be compared with what type of known standard?
Answer: A dental impression (dental stone cast) taken from the suspect's teeth
A dental stone impression of the suspect's teeth creates a three-dimensional model for direct physical comparison with the bite mark cast.