CRIME SCENE ASPECTS AND EVIDENCE HANDLING

• Jurisdiction: Australia

Introduction ................................................................................................... [88C.200]

Contamination ............................................................................................... [88C.220]

The GIFT principle ........................................................................................ [88C.240]

Packaging and labelling ................................................................................ [88C.260]

Conclusions ................................................................................................... [88C.280]

[88C.200] Introduction

There is a much-hackneyed phrase which, nonetheless, puts in succinct terms the effect that the crime scene examiner can have on the subsequent laboratory forensic examination of exhibits: "rubbish in, rubbish out", yet this is the unavoidable truth. Forensic scientists are constrained by the input and, as the discovery and collection of potential evidence is normally a police responsibility, it follows that they, and to be more specific, the scene examiners, have the critical role in determining the effectiveness of the laboratory investigation. The recognition, recording and recovery (the three Rs) of evidence are not trivial matters but are essential, as physical evidence can only be examined if its potential presence and value is understood by the crime scene examiner.

It is outside the scope of this chapter to consider crime scene examination in detail. For the interested reader, a selection of references is given in the Bibliography. In this section, some of the principles which apply to the work of a crime scene examiner are discussed, paying particular attention to the potential for fibre evidence recovery.

[88C.220] Contamination

Potential for contamination

Rarely will the crime scene examiner be the first person at a scene. Because of the nature of the job of a scene examiner, he or she will attend a scene discovered by someone else, a first responder, who will usually be a member of the public or a general duties police officer, often a relatively inexperienced officer. Thus, it is vital that all police personnel understand the potential to "contaminate" a scene and how this can be avoided.

A contaminant can be anything added to the scene that was not present at the time of the incident. This can range from fingerprints, sweat or other body secretions, dropped cigarette butts, hairs, clothing fibres, a footprint and so on. The increasing sensitivity of forensic analytical techniques has raised the "bar" in relation to the potential to contaminate a scene.

In this regard the increased sensitivity for the analysis of DNA is especially important as this has implications for the sequence of forensic examinations and how and when fibres should be recovered.

Prevention of contamination

The simplest way to avoid contamination is not to touch anything and to keep as far away as possible from the scene. In practice this can be difficult to achieve. If a body is found, clearly the person who finds it will have to check for the presence of vital signs; first aid or resuscitation measures may be necessary. These take priority over any other consideration. However, if deceased, the body should be disturbed as little as possible and the person should retreat some distance from the scene and stop...