1.3-Shortened

Types of Evidence

  • Evidence is crucial for investigating and prosecuting crimes.

  • Types of evidence:

    • Physical evidence: Tangible materials (e.g., DNA, weapons).

    • Testimonial evidence: Statements by witnesses, victims, or defendants.

Examples of Physical Evidence

  • Various forms including:

    • Body materials (e.g., blood, semen).

    • Impressions (e.g., tire tracks, tool marks).

    • Objects (e.g., weapons, hair, notes).

    • Footprints, bullets, and other pertinent materials.

Fingerprints

  • Latent fingerprints: Invisible; made visible using dust or ultraviolet light.

  • Patent fingerprints: Visible to the naked eye in substances like blood or dust.

  • Usage: Stored in databases; compared with crime scene prints for identification.

Locard’s Exchange Principle

  • Every contact leaves a trace, linking evidence to the offender.

  • Trace evidence can include hair, fingerprints, and bodily fluids.

Collecting Physical Evidence

  • Essential procedures:

    • Use gloves and protective gear to prevent contamination.

    • Proper packaging is critical: e.g., blood-stained fabric not folded.

Specific Types of Evidence Handling

  • Blood: Air dry and send to the lab within 24 hours.

  • Semen: Air dry, then package separately.

  • Saliva: Found from bites or chewing gum—samples can be swabbed.

  • Hairs: Package carefully for DNA extraction.

  • Clothing: Handle to avoid skin contact; package properly to prevent contamination.

High-Profile Case Example: JonBenét Ramsey

  • Notable failures in evidence collection led to contamination; case remains unsolved.

Evaluating Evidence Collection Procedures

  • Case analysis: Identify errors in the crime scene sketches and evidence packaging.

Testimonial Evidence in Court

  • Written or spoken statements must be disclosed pre-trial.

  • Includes physical evidence like CCTV footage.

Hearsay Evidence

  • Generally not accepted as valid in court.

Entrapment

  • Defined as tricking a defendant into confessing; example: Colin Stagg case.

Case Study: Barry George

  • Convicted of Jill Dando's murder, later acquitted due to evidence handling issues and lack of sufficient proof.