Unit 2: Criminal Justice Foundations

Law Enforcement Operations: Intro to Criminal Investigations

The objectives of an investigation into a crime or possible crime can be described by saying that an investigator seeks to determine what happened, when it happened, where it happened, how it happened, who did it, and why. The initial report that an officer receives will probably leave him at a loss in answering several of these questions completely. This section will discuss some techniques for answering these questions together with warnings of some of the more common pitfalls an investigating officer should anticipate.

At all stages of an investigation of a crime, an investigating officer should keep a notebook handy. Notes should be taken immediately after observations are made and in sufficient detail to enable the officer to recollect accurately at a later time the details of those observations. In the normal case, notes will be the starting point in writing more formal reports.

Whenever possible, it is also desirable to have a camera at every stage of an investigation.Often enough, pictures are “worth a thousand words.” A photograph which can be characterized by an observer as a fair and accurate representation of the object photographed can be invaluable evidence in determining the guilt or innocence of a subject.

When an officer receives a report which he determines should result in an investigation, his first responsibility is to make a note of the report or call, the precise time at which it was received and the name or other description of the person making the report or call, together with a note of how that person may be reached in the future. The person who responds to the call by commencing investigation must take care to recall the route of his travel to the scene, any observations made on the way which he believes may prove to be significant, and the time of his arrival at the scene. He should record his observations of the scene itself and the names of all witnesses or persons at the scene who may prove to have some information to contribute to the investigation.

When an investigating officer arrives at the scene of the crime, his first responsibility is to guarantee that the scene is not disturbed except to the extent necessary to allow aid to be given to any injured persons. If other officers are expected to come to the scene, the officer’s responsibility will be to preserve the scene, uncluttered and undisturbed. If it is necessary to move any objects which form a part of the scene, the officer must take great care to note the manner in which such alterations are made. The position of a body or piece of evidence at the scene can be crucial in determining the identity of the person to be charged, and his guilt or innocence. This goal of preserving the scene remains paramount until a thorough scene investigation has been concluded. This includes the taking of any objects of physical evidence, photography, and making of such measurements as will be sufficient to allow an accurate scene diagram to be prepared.

The next concern of investigating officers is the seizure of physical objects which may have value as evidence. The kinds of physical evidence for which an investigating officer should search will necessarily depend upon the nature of the crime or occurrence under investigation. The officer must be aware of whether he needs a search warrant to seize the physical evidence he observes. Because it is impossible to determine with complete certainty every item of property that will prove to be crucial at trial, it is important for the officer to completely document what is present at the scene, even if he does not have reasonable grounds to seize the item. A camera may prove invaluable in memorializing the scene. Certainly there is no theoretical limit to the kinds of physical objects which may function as evidence which tends to prove the existence of the elements of different crimes. Cases are solved every day by finding at the crime scene such items as matchbook covers, cigarette stubs, cartridge cases, spent bullets, and specimens of such things as blood, soil, hair, semen, thread and the like. The officer must particularly describe these items in a search warrant application and there must be probable cause to support the seizure of these items.