Evidence is only as strong as its weakest link.
Chain of custody is the documented life history of every piece of evidence — who handled it, when, where, under what conditions. A break in the chain doesn't just weaken a case. It can end one.
What the chain documents
- The exact context of recovery (location, depth, orientation, photograph).
- Who took the sample or item, when, with which equipment.
- Every transfer — from field to lab, from lab to court — signed and timestamped.
- Every analytical step performed, by whom, with which method.
- Where the item is stored, under what conditions, with what access controls.
Why this matters in court
A defence lawyer's first question about a forensic exhibit is: can you prove this is what you say it is, and that nobody has tampered with it?The chain-of-custody record is the answer. Without it, even a perfectly analysed sample can be excluded from evidence.
Where mass-grave investigations are vulnerable
- Unrecorded site visits. Disturbance of a site without documented authority can taint everything recovered after.
- Informal sampling. Samples taken without chain-of-custody discipline cannot be relied on, no matter how good the lab work.
- Storage gaps. A weekend in an unlocked room is a chain break.
The Minnesota Protocol
The 2016 revised Minnesota Protocol is the international standard for investigating potentially unlawful deaths, including mass graves. It requires that every action taken at a site be documented contemporaneously, that independent expert observers be allowed where possible, and that the process be transparent enough to withstand later scrutiny.
The TLTE position
The Chemmani chain of custody must be public and independently auditable. This is a standing demand of the ICRC and TRIAL International among others. TLTE endorses it.