How to Investigate Cold Cases as a Career

Detective With Recorder Asking Man at Police Station

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No matter how good police detectives may be, cases are going to come along which just can’t be solved. At least, that is to say, not right away. Once investigators have exhausted all available leads, the trail, as they say, goes cold. And so too does the case. 

Lack of evidence, lack of witnesses and lack of technology are just some of the factors that can converge to make a case difficult, if not impossible, to solve within a reasonably quick timeframe.

Criminal cases aren’t classified as “closed” unless and until there are a final determination and finding. That means evidence and testimony have generated probable cause to identify a responsible party for the incident in question (accidents and suicides included). Unsolved cases, then, remain open but inactive.

That means that, while investigators haven’t drawn a successful conclusion, they’ve since stopped actively working the file. These so-called cold cases remain open and inactive indefinitely unless new information or evidence surfaces that warrants taking a second look. And that’s where the job of a cold case investigator comes in. 

How Cold Case Investigations Work

The International Association of Cold Case Investigators defines a cold case as “any criminal investigation in which all known leads have been investigated, and evidence is being re-examined to determine if further scientific analysis is necessary.”

There are a few ways that a cold case may be reactivated, but in general, they involve the revelation of some new fact that compels further investigation. In some few instances, police departments have an investigator assigned to review cold cases.

In even rarer circumstances, agencies have an entire squad or unit dedicated to cold files. In these instances, the investigators may initiate periodic reviews of cases to see if anything may have been overlooked or if any new information might be available. If so, they’ll pursue those new leads and see where they take them in hopes of bringing some resolution.

The majority of cases, though, are reactivated because some outside source brought new information to light. For example, a previously unknown witness may surface with crucial information. Or, as in one New York City rape case, DNA evidence from a cold case appeared as a match to other evidence gathered in a new case, linking the two and providing valuable new leads.

If a department doesn’t have a dedicated cold case investigator or unit, an investigator is assigned to go after the new leads and work it as he or she would work a fresh case. They’ll review the old files and interviews and, if necessary, conduct new interviews in light of the new information.

Where Cold Case Investigators Work

According to a 2011 study by the RAND Corporation, only 20 percent of law enforcement agencies in the United States have a protocol in place for initiating cold case investigations. Only 10 percent have a full-time investigator assigned to cold cases, and only seven percent have a dedicated cold case unit.

These departments are typically larger metropolitan police or sheriff's departments, such as the NYPD or LAPD, and federal or state investigative bureaus like the FBI or Texas Rangers. Smaller agencies may sometimes hire retired or former detectives on a part-time basis to handle cold cases as the need arises.

How Much Cold Case Investigators Earn and How You Can Become One

Cold case investigators are criminal investigators; they have essentially the same working responsibilities and rank as other detectives or investigators. In the United States, the average salary for full-time investigators is around $60,000 per year, but that figure can vary greatly depending on years of service and location.

To become a cold case investigator, you must first become a police officer or special agent. Like any other specialty position or unit within law enforcement, after you have enough seniority, you may become eligible to become a criminal investigator and possibly be assigned to a cold case unit.