Basic principles – preserve

What is it that we are going to preserve, and how will we do this?

Part of the answer is that there is a blurring of control and preserve, and what happens depends on the crime and the scene.

The first is discussed from the perspective of major crime or volume crime. The major crime part is easy – murder, rape, bombings, all fall naturally into this category, and the response is also easy, with a full deployment of resources to prevent changes to the scene such as loss or contamination. Volume crime includes house-breaking and has often been treated as minor and not worth bothering about. However, when it was discovered that DNA databases were producing links between minor crimes and major ones, the responsiveness to volume crime became more critical in order to preserve vital DNA evidence.

The video discusses the use of cordons to control scenes and prevent their degradation, and shows how this is simpler in well-contained indoor scenes than in less well-defined outdoor ones.

The main part of the video deals with the specifics of preservation against contamination and the environment, and the preservation of the different kinds of materials identified and collected from a scene.

These are all about preservation of the physical integrity of the evidence, and the final preservation element considered is legal integrity, or chain of custody.