forensics chap 2

locards principle of exchange

states that when a person comes into contact with something, a cross transfer of physical evidence can occur

physical evidence

a type of circumstantial evidence that includes fingerprints, marks, fibers, weapons, and imprints

trace evidence

a type of circumstantial evidence that includes hair, blood, and soil that was tracked

two types of evidence

direct- eye witness acccount

circumstantial- finding suspects weaponfinger prints

class evidence

limits suspects to group of people - specific type of hair

individual evidence

limits suspect pool to one person - fingerprints

responsibilty of first officer at scene

secure scene and direct activity

why separate witnesses

to limit them talking/sharing stories

method for photographing a scene

triangulation- mix of closeups/wide shots

3 ways of crime scene recording

record data, sketch scene, take photos

what is rough draft

the first sketch made by the crime scene sketcher that includes basic layout and measurements

4 common search patterns

Grid, linear, quadrant/zone, or spiral

which is used in solo invesyigating

grid, linear, spiral

what is used in group

linear, zone/quadrant

7 S’s

-securing scene

-sperating witnesses

-scanning scene

-seeing scene

-sketching the scene

-searching for evidence

-securing and collecting evidence

keep all evidence in separate containers in order to

limit cross contamination

what container is best for holding hair, glass and fiber

paper bindle/druggist fold

what is paper bindle/druggist fold

a method of folding paper to form a secure pocket

why never put wet evidence in air tight containers

it needs to dry out first in a paper bag to prevent the growth of mold

chain of custody

the documented and unbroken transfer of evidence

datum point

a permanent and fixed point of reference when mapping a crime scene

sub datum point

the corner of crime scene, determined by measurements from satum point

crime scene reconstruction

an hypothesis of the sequence of events before the crime was commited

staged crime scene

fake or staged

type of crimes that are often staged

arson to cover tracks, murder by saying it was suicide, and bulgary to collect insurance money

points to consider if smth is staged

• treat all deaths as homicides

• see if wounds are consistent with weapons found

• see if wounds could be self-inflicted

• establish victim profile

• establish mood of victim before death

• establish mood of suspects

• corroborate statements with evidential facts

• reconstruct the event