Evidence Collection, Chain of Custody, and Admissibility
From seizure to courtroom
Evidence must be relevant, authentic, and in the form the rules require. Authentication means showing the item is what the proponent claims it is - usually through witness testimony, distinctive characteristics, or metadata. The best-evidence rule prefers originals for writings, recordings, and photographs, though duplicates are generally admissible absent a genuine dispute about authenticity. Hearsay rules matter: an investigator's report is often offered under a business-records or public-records exception, and the investigator may need to lay that foundation personally.
Chain of custody
Every item needs an unbroken, documented path from collection to presentation. A workable form captures: item description and unique identifier, date and time collected, location, collector, every transfer with signatures, storage location, and seal condition. Digital evidence adds hash values at acquisition and verification before use. Breaks in the chain do not automatically exclude evidence; they go to weight, unless the gap creates a genuine question of tampering or substitution.
Traps
- Confusing weight with admissibility - a gap usually damages credibility rather than triggering exclusion.
- Submitting screenshots without capturing the source URL, timestamp, or device context.
- Failing to document who else had access to a stored item.
- Assuming copies are always acceptable when the original is available and disputed.
Rule of thumb
Bag, tag, log, seal, store. One item, one entry, one signature per transfer - and record the time in a consistent format with time zone noted.