Summarize the 'role' of the evidence from a crime scene below?Evidence :- 1. Hair 2. Blood 3. Fingerprint 4. Drug 5. Electronic data (such as a USB)
Well, the obvious answer for the first three is that such evidence helps to identify or narrow down the list of suspects for said crime. Each, with the help of DNA and/or crime databases leaves a specific identifier that can often be tied to people with existing criminal histories.
This is true in part for the USB evidence, since that often traces information about the nature of the crime back to a specific computer and/or computer user. Depending on what is on the USB stick, it can also contain evidence of a crime, or multiple crime, or can be used as cross-referencing to other criminals or criminal activity present in the files on it.
For the drug evidence it depends. If we are talking about drug residue or the actual drugs found at a crime scene, it can establish guilt by possession or intent to deliver. If we are talking about drug content in a blood sample, say, then it can confirm the perpetrator's state of mind at the time of the crime itself, and perhaps clarify the motive.