field science
A branch of forensic science involving crime scene analysis
lab science
A branch of forensic science involving chemical and physical analysis of evidence.
medical science
A branch of forensic science involving pathology, determination of injury, psychology and other biological areas of study
Locard's Exchange Principle
Every contact leaves a trace
Seven S's of Crime Scene Investigation
1. Secure the scene
2. Separate the witnesses
3. Scan the scene
4. See the scene
5. Sketch the scene
6. Search for evidence
7. Secure and collect evidence
individual evidence
material that can be related to a single source; fingerprint, DNA
Known Evidence
evidence that can be traced back with certainty to a specific source
non-physical evidence
non-tangible evidence, smell, or witness testimony.
Physical Evidence
tangible items that tend to prove some material fact; also called real evidence
class evidence
Material that connects an individual or thing to a certain group
4th Amendment
Freedom from unreasonable searches and seizures
chain of custody
the documented and unbroken transfer of evidence
Are fingerprints unique?
fingerprints are more unique than DNA. No 2 people have ever been found with the same prints. (identical twins have same DNA)
Galton
fingerprints dont change with age
Loop
a fingerprint pattern in which the ridge pattern flows inward and returns in the direction of the origin
Whorl
fingerprint pattern with at least two deltas and a core.
arch
formed by ridges entering from one side print, rising in the center and exiting the opp. side of print. No core or delta
latent fingerprint
a hidden fingerprint made visible through the use of powders or other techniques
plastic fingerprint
A visible fingerprint impression deposited by contact with a soft material.
patent fingerprint
a visible fingerprint that happens when fingers with blood, ink, or some other substance on them touch a surface and transfer the pattern of their fingerprint to that surface
fingerprint identification system
1. Analysis
2. Comparison
3. Evaluation
4. Verification
Passive Stains
Patterns that result from gravity such as drops and pools of blood from a wound or injury
Transfer Stain
result of some object coming into contact with a pool of blood and being transferred to another area of surface
Splatter of projected stains
stains that occur with impact and cause blood splatter
wipe stain
bloodstain is removed or altered because a non-bloody object has moved through a wet bloodstain.
cast off
blood that is thrown from an object in motion
expiatory stain
blood that exits body after and internal injury blood exits through nose or mouth
point of convergence
Starting point of the bloodshed event
3 types of blood stains
passive, transfer, projected
4 Nitrogenouse bases
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
3 parts of a nucleotide
nitrogenous base, pentose sugar, phosphate group
dna found?
cells, saliva, hair roots, body tissue
fire recipe
oxygen + Fuel + Heat =?
Ballisitics
the study of the dynamics or flight characteristics of projectiles
Greiss Test
A chemical test used to develop patterns of gunpowder residues around bullet holes
1. Fresh
- autolysis
- release of cellular components into tissues
- beginning stages of putrefraction
2. Bloat
-putrefaction, fluids begin to leach from orifices
- gastric bloating
- start to smell
3. Active decay
- continuation of putrefaction
- additional leaching of fluids
- rupturing of gastric cavity
- adipocere formation in moist environments
- tissues break down
4. advanced decay
- reduction/cease of chemical decomp processes
- continued decomp or removal of soft tissues
- mummification may occur
- liquification of tissues
5. dry
final stage in the decomposition process. Skeletal or remains stage. characterized by all moisture being absent and nothing but bones and connective tissue present.
lacerations
splitting of the skin by the direct crushing of blunt trama
puncture
(n.) a small hole made by a sharp object; (v.) to make such a hole, pierce
Algor Mortis
Post-mortem cooling of the body to the surrounding temperature.
liver mortis
The pooling of the blood in tissues after death resulting in a reddish color to the skin
rigor mortis
stiffness of the body that sets in several hours after death
Coroner
an official who investigates death not due to natural causes
Ovoviviparous
a mode of reproduction in animals in which embryos that develop inside eggs remain in the mother's body until they are ready to hatch.
questioned document
any document about which some issue has been raised or that is the subject of an investigation
Examplar
sample of handwriting whose source is known and used for comparison with a questioned document