Scene Investigation, Evidence Recognition, and Documentation
Photograph in three scales
Every scene image should answer "where," "what," and "how big." Begin with establishing/overall photographs that place the decedent in the environment, move to mid-range views of the body and surrounding objects, then close-ups with and without a scale. Photograph before and after any movement. Note unusual lighting, and use oblique lighting or alternate light sources when fluids or trace may be present.
Sketch and measure
A rough sketch with fixed reference points and measured distances converts a photograph into a diagram. Include a North arrow, doorways, furniture, bloodstain patterns, and body position. Notes should be contemporaneous and time-stamped.
Evidence recognition and preservation
The investigator's core duty is recognition and preservation; collection authority varies by agency. Maintain an unbroken chain of custody - every transfer documented with date, time, from, to, and seal condition. Package biological evidence in paper so it can air-dry; sealed plastic traps moisture and degrades DNA. Sharps go in rigid containers, and wet items are dried before packaging. Inventory personal property with a witness and issue a receipt.
Common traps: placing bloodstained clothing in a plastic bag; signing for evidence you never handled; failing to note that EMS moved the body or cut clothing; collecting a digital device and then opening it.
Rule of thumb: if it is not written down and photographed, it did not happen - document the ordinary as carefully as the dramatic.