A number of different evidence tracking methods are used by law enforcement agencies all over the world to control, monitor, and secure evidence in their care. These systems range from computer systems with highly automated functionality to more old fashioned systems, such as handwritten logs. In some regions, modernization requirements from national governments have forced law enforcement agencies to adopt computer evidence tracking systems in order to comply with regulations.
Evidence is a key part of criminal investigation. There are a number of legal and ethical requirements involved with evidence handling, ranging from collecting the evidence in a way that reduces the risk of contamination to maintaining chain of custody and ensuring that the evidence is always accounted for. Evidence tracking is used to log items into evidence, to keep track of them as they are moved, and to enter final notes about the disposition of evidence after it is no longer needed.
Development of evidence tracking systems starts in the field, where the evidence is collected. Computer systems often have portable functionality, allowing criminal investigators to tag evidence with bar codes or radio frequency identification (RFID) tags at the time it is collected, and to enter notes into the system to describe the evidence, note who collected it, and provide other information. These systems also interface with cameras so that pictures of the evidence in situ can be attached to the evidence log for future reference. Other systems may require people to copy information from bags and boxes used for evidence collection to a handwritten log or non-portable computer system in the evidence room.
Once evidence returns to a law enforcement agency, an evidence tracking system must be able to indicate where the evidence is and to maintain a log of every time the evidence is moved. Evidence can be out for examination, in use in court, or in long term storage. It can also be destroyed or sold if it is no longer needed. An evidence tracking system must have a mechanism for recording activities involving given pieces of evidence, whether it is a log attached to an evidence bag and signed by people who interact with the evidence or a computer record.
Several companies make computerized evidence tracking systems that can be purchased in packages by law enforcement agencies. These systems usually operate with bar codes or RFID. It is also possible to buy packaged physical tracking systems, including forms to attach to evidence, logs maintained by personnel who supervise areas where evidence is held, and paperwork for documenting the final disposition of evidence.