Regardless of the nature of a criminal case, there are certain standard investigative techniques that should be followed by law enforcement personnel even before the gathering of evidence begins. One of the most important aspects of the investigation must be the preparation of a report to be used as a permanent record of the significant facts and findings of a case. With an eye toward the eventual presentation of the facts in a court of law, investigators must determine how the report will be structured. The content must be accurate, objective, and complete. The form of the report must be clear, concise, and grammatically correct. Once the game plan for the preparation of a report is determined, the investigation is ready to begin.
While searching for initial clues at the scene, photographs should be taken before any evidence is moved and a sketch of the scene should be drawn. In the case in question, the significant clues to be examined might include at the very least the following:
- dirt and dust particles
- fingernail scrapings
- fingerprints, both visible and latent
- fragmented objects
- organic and inorganic materials
- personal possessions
- bullets and cartridges
- notes, letters, pictures, or documents
Investigators should slowly, cautiously, and methodically walk through the crime scene making sure not to disturb or contaminate any evidence. Markers should be placed near the victims, the blood and bloodstains, visible fingerprints or footprints, the location of weapons, and any other evidence preliminarily determined to be important, which evidence can later be carefully gathered and protected for an in-depth examination.
Since the present case involves deaths, investigators should separate the location into two distinct categories in order to obtain clues and evidence. The primary crime scene would be the area where the two bodies are located and most of the physical evidence is present. Secondary crime scenes are areas where anything related to the apparent crime is found. Physical evidence gathered from a secondary crime scene would ordinarily be removed and separated from the primary crime scene for analysis.
Subsequent to the initial examination of the potential crime scene, interviews would begin. Investigators must determine whether there are witnesses with first-hand knowledge of the incident. Other witnesses might have insight into the backgrounds of the deceased parties, such as domestic violence, prior police involvement, unreported assaults, or complaints that might provide greater insight into the incident. The identities of the victims must be ascertained.
Of utmost importance in all investigations is the preservation of the evidence gathered and the chain of custody followed from the initial stages of the investigation through the trial of any resulting court case.