What type of evidence is particularly fragile during rape investigations?

Physical forensic evidence is particularly fragile during rape investigations due to its susceptibility to contamination, degradation, and loss. This type of evidence can include bodily fluids, hair, fibers, and other trace materials that are essential for linking a suspect to the crime. Once a crime scene is disturbed, or once time passes, these elements can easily be altered or destroyed, making it crucial for investigators to secure and collect this evidence as promptly and carefully as possible.

In contrast, while video evidence and digital evidence can also be important, they are generally more durable and can often be preserved longer with the right technology. Witness testimonies, although they can be influenced by many factors including time and stress, are not as prone to physical degradation as forensic evidence. Thus, it is the physical forensic evidence that requires the most careful handling during rape investigations.