SCI-102: firearms & tool marks

Firearm and tool mark examiners use ___ to associate an evidentiary item with a source

microscopic comparisons of markings

crime scene reconstruction

method used to develop a likely sequence of events by the observation and evaluation of physical evidence, as well as statements made by those involved with the incident

In 1892 ___ published his classic textbook Finger Prints

Francis Galton

At Galton's insistence, the British government adopted fingerprinting as a supplement to the ___

Bertillion system

5 manners of death

1. homicide

2. suicide

3. accidental

4. natural

5. undetermined

Latent prints deposited on hard and nonabsorbent surfaces are preferably developed by the application of a ___

powder

prints on porous surfaces generally require treatment with a ___

chemical

2 types of handguns

1. single shot pistols

2. revolvers

single shot pistols fire ___ round(s) at a time

1

3 types of revolvers

1. swing out

2. break top

3. solid frame

lands

The surfaces of the original bore remaining between the grooves

3 fingerprint principles

1. fingerprints are individual characteristics (no 2 are the same)

2. fingerprints remain unchanged over lifetime

3. fingerprints have general ridge patterns permitting them to be systematically classified

4 common fingerprint ridge characteristics

1. bifurcations

2. ridge endings

3. ridge dots

4. enclosures

ACEV

Analysis, Comparison, Evaluation, Verification

___ aids in classifying and retrieving fingerprints by converting the image of a fingerprint into digital minutiae that contain data showing ridge endings and bifurcations

AFIS

3 ACE-V levels

1. general ridge/pattern makeup

2. comparing ridge characteristics

3. ridge pores/permanant minutiae 

4 cartridge characteristics

1. firing pins

2. breech block/backing plate

3. extractors/ejectors

4. magazine lips

Goal of initial examination of a fired bullet

determination of rifling characteristics

5 general rifling characteristics

1. caliber

2. # of lands/grooves

3. direction of twist

4. degree of twist

5. width of lands/grooves

NIBIN

national integrated ballistics information network

striations

fine lines found in the interior of the barrel

___, ___, and ___ offer a highly distinctive signature for individualization of cartridge cases

firing pin, breechface, and ejector and extractor mechanism

7 types of evidence sent to autopsy

1. swabs (victim, gunshot residue, body)

2. clothing

3. fingernail scrape 

4. hair comb

5. buccal swab

6. vaginal/oral/anal swab

7. recovered bullets