Trace Evidence – Individual vs. Class Evidence

Notes on page 31 in notebook
A very small
piece of
evidence that
can be used to
identify or link a
suspect to a
Derived from Edmond Locard’s Exchange
 Every contact leaves a trace
 There will be small transfer of evidence during the
commission of the crime
Divided into individual or class evidence
Individual evidence shows an object’s
Can specifically place things to a person or
a place or an object to the exclusion of all
DNA, fingerprints, some footwear
impressions, bite marks, bullets
Class evidence can place an object to a
group, but not to an individual
Will include a group of suspects
Examples: fibers, paint, soil, glass
A student is kidnapped on the way home
from school. Her backpack is found on the
side of the road. There are several strands of
hair caught in the zipper. Is this individual or
class evidence? Explain why.