Three-Tier Perimeter
Definition
The cordoning standard. An inner cordon around the body and evidence, a middle cordon around the search area, an outer cordon around spectators and media.
- Inner cordon
- Immediately around the body and physical evidence
- Middle cordon
- Encloses the wider search and approach area
- Outer cordon
- Keeps spectators, press and traffic back
- Access control
- Only tier-appropriate personnel cross each line
Common questions
Who is allowed inside the inner cordon?+
Only personnel with a direct evidentiary task there: the scene examiner, photographer and, briefly, the pathologist or medical examiner. Everyone who crosses signs and times an entry log, which is why unnecessary crossings are avoided.
Why keep a separate middle cordon instead of just one line?+
The middle cordon gives searchers and support staff room to work without repeatedly crossing the inner line, and it lets investigators expand or shrink the search area as new evidence is found without disturbing the tightly controlled inner zone.
Related terms
- Finished Sketch
- Off-scene drawing made later, to scale, with legend and compass. The courtroom version.
- Rough Sketch
- On-scene freehand drawing with measurements, not drawn to scale. Made in the duty diary in pen, never erased.
- Scene Log
- The contemporaneous record of every person entering and exiting the inner cordon, with time stamps and roles; the foundational chain-of-custody document for...
- Triangulation
- Comparing independent quantitative and qualitative findings on the same research question to check whether they converge, add to each other, or contradict.