Only after documentation is complete does the collection of evidence begin. This is a task governed by strict protocols to prevent contamination. Investigators wear protective clothing—not to protect themselves, but to prevent their own hair or skin cells from contaminating the scene. Every item collected is sealed in a container and labeled, initiating the "chain of custody." This legal term refers to the documentation of who has handled the evidence from the moment of collection until it is presented in court. A broken chain of custody can render critical evidence inadmissible, potentially jeopardizing the entire case.

(i) The Danger of Lab Contamination (ii) Securing and Assessing the Initial Scene (iii) How to Package Biological Samples (iv) Creating a Permanent Record (v) From Physical Evidence to Courtroom Story

As a forensic scientist, I had been called to the scene of a crime to help investigate and gather evidence. The police had received a report of a break-in at a local jewelry store, and the owner had been found dead.

: Once a SOCO arrives, they wear full protective gear—suits, gloves, masks, and overshoes—to avoid adding their own DNA or fibers to the scene.