No department has unlimited time, personnel, and resources so it’s important to carefully select the cases for review. Violent persons crimes are particularly well suited to cold case review. The reason for this is simple; homicides and sexual assaults tend to yield the most evidence.
Once the types of crimes that you will be re-examining have been determined, it’s time to define the parameters for selecting specific cases. This will be totally dependent upon the agency and caseload.
For example, it might be reasonable for smaller agencies to look at all unsolved sexual assaults and/or homicides over the last decade. Larger agencies, however, will have to select a limited number of cases based on several factors, including the amount and condition of the physical evidence, the whereabouts of previously identified suspects and witnesses, and the overall severity and brutality of the crime.
If your department has a crime analyst, he or she will be a great resource to help you decide which cases to reopen. Your crime analyst can sort through and filter all reported crimes and give you a list of cases that meet the criteria. If your agency doesn’t have a crime analyst, talk to senior detectives and other long-time personnel. Without a doubt, “old-timers” will remember cases that have gone unsolved for 10, 20, or even 30 years.
Time can be the enemy of some investigations, so ask yourself if the case is too old. A few factors determine whether a case is too old to reopen. First, you need the evidence. So before you reopen a 50-year-old homicide, check with the property and evidence room and see if they still have the physical evidence. Second, you need the parties who were involved in the crime. If you think the key witnesses, victims, and suspects have died, there’s probably little point in reopening the case.