In order for physical evidence to be analyzed and to tell its part of the story of a criminal incident, it must first be properly collected. In order for the proper collection to take place, the crime scene, which contains the physical evidence, must be properly secured, protected, and preserved. This scene security, protection, and preservation is the responsibility of any and all law enforcement personnel who come in contact with the scene, the suspect, and/or the victim. What is presented during this block of instruction is a brief introduction to various types of evidence, with emphasis on physical evidence, crime scene management, mainly on the duties and responsibilities of the responding investigator, and a brief overview of the properties of physical evidence.

Important Definitions

Crime Scene

• A place where a crime has taken place.

• A starting point for a criminal investigation.

There is no "crime scene exception" to the Fourth Amendment.  That is, once the emergency is over, and police have secured the scene, then the police must comply with Fourth Amendment requirements.  If the scene is a protected area such as a house or private part of a business, then a search warrant or consent (in writing preferred) from the person in possession must be obtained.  Of course officers can secure and protect the scene until these requirements are met (Flippo v. West Virginia).

Crime Scene Search

Locating, identifying, and collecting that tangible material which may associate a given individual (suspect and /or victim) with the crime scene and, subsequently, the crime.

Evidence

"Anything which is legally submitted to a competent tribunal as a means of ascertaining the truth of any alleged matter of fact under investigation before it"

Direct evidence

"That which (if true) proves the fact in dispute ... in the case of a witness...it is the result of personal knowledge derived through one or more of the five senses"

Indirect or circumstantial evidence

"That which (if true) tends to establish an issue in dispute by proving another fact...[it] does not . . . conclusively establish that issue, but causes an inference or presumption of its existence"

Real or physical evidence

• "May include almost any (tangible) object...that is directly linked to crime charged and may be observed by a judge and /or jury"

• Circumstantial physical evidence

Example: Witness testimony that an accused was known to own a revolver of the same make and caliber of that used in the commission of a homicide.

Testimonial evidence

• "That which is supplied through the verbal testimony of a witness (or suspect)"

• Circumstantial testimonial evidence

Example: The perpetrator of a crime was observed wearing a red shirt with vertical blue stripes; the individual accused of the crime owns such a shirt.

Value of Physical Evidence

Physical Evidence Versus Testimonial Evidence

Human factor

• Physical evidence "can't lie, quit, die, forget, or get fired"

• Testimonial evidence may change or source may become "nonexistent' between original and court version

Physical properties

• Cannot change

• Only interpretation can change or be in error

Circumstantial Variability

If the item of physical evidence is found and subsequently associated with a suspect where the suspect had no right to be, then (when identified) the evidence may:

• Establish a suspect's presence at the crime scene.

• Establish probable cause.

• Establish proof beyond a reasonable doubt.

If the time of physical evidence is found where a suspect may have had a legitimate right to be (innocent access), then the evidence may:

• Have no significance.

• Provide leads to follow to establish the case via other sources.

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Crime Scene Management