They must insure that the chain of custody is maintained. They must properly mark all evidence prior to collection and account for it at all times until a case is solved. Investigators may prepare detailed sketches of the crime scene to augment photographs or videos. Sketches allow the investigator to illustrate the location and relationship of all evidence to the crime scene. Accurate measurements are taken from fixed locations to each piece of evidence so the investigator can provide specific information to its location and its relationship to all other evidence collected.
Collected evidence is processed in a forensics laboratory.
Investigators may use chemical processing, fluorescent powders, alternate light sources and photography to enhance fingerprint images. Investigators may use the Automated Fingerprint Identification System to identify latent fingerprints. Forensic investigators may be either civilians or sworn officers. They often work in a laboratory equipped with chemicals and instruments, but may routinely collect evidence at the scene of a crime where they may be subjected to unpleasant sights. Investigators may work day or night shifts and may be required to work for extended hours in order to process evidence for a pending case.