Understanding Crime Scene Fundamentals

This section introduces the fundamental principles of forensic investigation and evidence classification. The content explores Locard's Principle of Exchange in Crime Scene Investigation and various types of evidence encountered at crime scenes.

Definition: Locard's Principle of Exchange states that when two objects come into contact, there is always a transfer of material between them.

Highlight: The extent of evidence transfer depends on three key factors: intensity, duration, and nature of contact.

Vocabulary: Trace Evidence refers to small-scale physical evidence transferred during contact.

Evidence is classified into several categories:

• Direct evidence: Based on firsthand observations
• Circumstantial evidence: Implies facts rather than directly proving them
• Physical evidence: Includes fingerprints and tire marks
• Biological evidence: Encompasses blood, DNA, and other biological materials

Example: Class evidence might identify a group (like shoe size), while individual evidence can identify a specific person (like DNA).

The crime scene investigation team typically includes:

• Police officers and detectives
• Medical examiners (for cases involving deceased victims)
• Various forensic specialists