What is the primary purpose of a preliminary test at a crime scene?

The primary purpose of a preliminary test at a crime scene is to identify or categorize materials. This initial testing is crucial as it helps investigators quickly determine the nature of the substances found at the scene, which can guide further investigative priorities and strategies. For example, identifying whether a substance is blood, drugs, or some other material can lead to different avenues of inquiry and evidence collection, influencing the overall direction of the investigation.

Preliminary tests serve as a starting point, allowing investigators to make informed decisions about which materials may need to be collected, analyzed, or further tested in a lab setting. This quick categorization contributes significantly to managing the crime scene effectively and ensuring that vital evidence is preserved and documented.