8127/frame/fm

 
Figure 8.1
 
Cigarette butt in the toilet.
When found at a crime scene, it is hoped
that one of the responding officers did not deposit this evidence.
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195
 
Good Field Practice — 
 
Processing a Crime Scene
A.
The Questions ....................................................................................... 196
B.
The Crime Scene................................................................................... 196
1.
What Is a Crime Scene? ................................................................ 197
a.
What Is the Scope of a Crime Scene?................................... 198
2.
Processing the Scene...................................................................... 198
a.
Check for Survivors ............................................................... 198
b.
Secure the Scene..................................................................... 200
c.
The Dynamic Crime Scene.................................................... 202
d.
The Team Approach............................................................... 203
e.
Assess the Scene...................................................................... 203
f.
Documentation ...................................................................... 206
i. Chain of custody .............................................................. 206
C.
The Evidence ......................................................................................... 207
1.
Recognition .................................................................................... 207
2.
Detection........................................................................................ 207
a.
Presumptive Testing ............................................................... 208
3.
Collection and Preservation ......................................................... 208
a.
Collection Procedures ............................................................ 209
b.
Preservation ............................................................................ 210
i. Nonbiological evidence ................................................... 210
ii. Biological evidence........................................................... 210
4.
Contamination............................................................................... 210
a.
Definition of Contamination ................................................ 210
b.
Sources of Contamination..................................................... 212
c.
Types of Impurities and Their Consequences ..................... 213
i. Nonbiological impurities................................................. 213
ii. Biological impurities........................................................ 214
d.
Prevention and Detection...................................................... 215
e.
Explainable Differences.......................................................... 217
D.
Summary ............................................................................................... 218
References ...................................................................................................... 218
8
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Principles and Practice of Criminalistics
Always look up.