Chain of custody,
defined link by link.

Every item of evidence has a history: someone found it, someone packaged it, someone carried it, someone stored it, someone retrieved it. Chain of custody is that history reduced to documentation: a continuous, signed record of possession and handling that accounts for the item at every moment between collection and courtroom. The test is simple to state. A stranger reading the file should be able to account for the item, hand to hand and shelf to shelf, without meeting a gap the file cannot explain.

The requirement is not ceremony. It is how an investigation proves that the thing presented later is the thing collected, unaltered and complete. National standards, model policies and training curricula, from IACP model policies to CALEA accreditation standards to academy and field training instruction, treat custody documentation as a baseline competency of evidence handling, which is what makes it a practices question long before it becomes a courtroom question.

Custody is also an institutional discipline, not a per-item habit. Accepted practice expects agencies to run their evidence functions so that documentation happens every time: intake standards, storage security, periodic audits, and accountability when the records do not balance. A single broken chain says something about an item. A pattern of them says something about an operation.

Breaks rarely announce themselves. They surface as small documentary contradictions: an item that appears in a report but not in the scene log, a seal opened without a notation, a transfer no receiving signature acknowledges, hours between collection and intake that nothing accounts for, a description that changes between the log and the laboratory submission. Finding them is a matter of reading the file against itself, the same discipline described in building the record chronology, and it starts with how the scene was handled in the first place, covered in crime scene documentation standards.

At the practices level, a gap is an investigative deficiency: the investigation failed to document the handling of evidence the way accepted practice requires, and the report says so plainly, with the gap located and the standard identified. What follows legally from a break, suppression, weight, admissibility, is counsel’s lane, and the report does not cross into it. Legal conclusions remain counsel’s; the expert addresses police practices.

Custody gaps also seldom travel alone. A record that cannot account for its evidence often cannot account for its witnesses or its timeline either, and the same review that finds one deficiency tends to find its siblings. That wider reading, through homicide, shooting and serious-felony records, is where custody review meets wrongful-conviction review casework.

A documented break is a finding about the investigation, not a conclusion about admissibility. The report states what the record shows and stops there; the legal consequences are counsel’s to argue.