What is defined as physical evidence that may be lost forever if not immediately preserved?

Transient evidence refers to physical evidence that is temporary in nature and can easily be altered or lost if not preserved quickly. Examples include odors, temperatures, or marks that can change or disappear under certain conditions. This type of evidence often requires immediate collection or documentation to ensure that it remains available for analysis, as environmental factors can cause it to degrade or vanish entirely.

In contrast, class characteristics refer to features that can be associated with a group, such as the tread pattern on shoes that doesn’t identify a specific pair. Individual characteristics are unique to a specific item, such as a tool mark that matches a specific tool. Associative evidence connects a suspect or victim to a crime scene, but it doesn’t necessarily share the same immediate preservation concerns as transient evidence. Transient evidence is critical in investigations, as it can provide immediate insights or lead to crucial links, emphasizing the importance of prompt action by investigators.