Crime Scene Investigation and Documentation
Crime Scene Investigation and Documentation
This domain tests how you manage a scene from first response through release: securing boundaries, keeping a scene log, conducting a systematic survey, and producing notes, photographs, and sketches that let another examiner reconstruct the scene without visiting it.
Core rules
- First responder priorities in order: officer safety, medical aid, scene security, witness identification, then notification. Do not process before the scene is stabilized.
- Document before you collect. Every item gets a description, location, and orientation in notes, photographs, and sketch before it is moved.
- Use one coordinate system consistently: triangulation from two fixed reference points, baseline offsets, or polar coordinates from a fixed origin. Record the datum and units.
- The rough sketch is a measured field record; the final sketch is a scaled presentation. Both must agree with photographs and notes.
- Maintain a scene log: name, agency, time in/out, and purpose for every person.
Worked example
A bullet casing lies 2.4 m from the north wall and 1.1 m from the east wall. Record it by triangulation using the room's northeast corner as datum: measure the shortest distance to each wall at right angles, note height above floor, and photograph the tape measure in frame. If the corner is not fixed, use two permanent reference points, such as a door frame and a window sill, and record the distances. The reasoning: wall offsets are reproducible only if you state which wall and which corner; ambiguity in the datum is a documentation defect.
Traps
- Photographing the scene after items are moved.
- Sketching 'not to scale' without a measured rough sketch.
- Omitting the datum or units.
- Using a single overall photo with no midrange or close-up.
- Log gaps that break continuity.