Other Impressions What other impressions can you think
- Slides: 11
Other Impressions • What other impressions can you think of at a crime scene? • Shoe • Tire • Fabric • ? ? ? • How are impressions preserved?
Lifting Impressions • Two methods: 1) similar to lifting prints, 2) electrostatic lifting 1. If made in light deposits of dust or dirt, place lifting material over impression, use fingerprint roller to eliminate air pockets, and lift impression.
2. Electrostatic Lifting (dust impressions) • Electrostatic charge on comb and tissue paper example • Mylar film placed over dust mark and pressed against impression with roller • Electrostatic unit gives a charge to the film, attracting the dust
2. Electrostatic Lifting (dust impressions)
Casting Impressions • Class I dental stone (gypsum) is used to make casts of shoe and tire impressions. • Cast needs to dry 24 -48 hours before transporting to the lab. • For snow impressions, spray with Snow Impression Wax, then pour Class I dental stone to make cast.
Casting Impressions, cont… • http: //www. sccja. org/csr-cast. htm
Casting Impressions, cont… • For shoe impressions in blood, the impression is “developed” and enhanced using various chemicals.
Case Study • O. J. Simpson
Bite Marks • How would bite marks differ from person to person? • What are the odds of two people having the same bite marks? • How are bite marks detected? – Visible – UV light
Bite Marks, cont…. • How is evidence collected? – 1 st step: – 2 nd step: • It’s like playing the game Operation. • Ted Bundy
If you think you can you can poem
Dhirubhaism
Mark made when surfaces slide across one another:
So you think you can argue
So you think you can argue
You can argue
If you can imagine it you can achieve it
If you cannot measure it you cannot improve it
If you can't measure it you cannot improve it
If you don't measure it you can't manage it
Langfristiges fremdkapital
Oh the thinks you can think quotes
