Fingerprints led to charges in a nearly 10-year-old cold case this week. The Hamilton County District Attorney's cold case unit ran old evidence through a fingerprint database and turned up a match that wasn't there nearly a decade ago.

Channel 3 wanted to know how often investigators check old evidence against new fingerprints.

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"Thumb and you would get a roll of the finger too," Officer Krystl Wofferd said while explaining Hamilton County’s fingerprinting system.

Every person charged with a misdemeanor or felony crime in Hamilton County goes through the process. Fingers and palms are digitally documented and entered into a national database, where they stay indefinitely. It’s a goldmine of potential suspects for investigators hoping to solve cases.

"That's extremely important if they have fingerprints to be matched up in the system to help crack the case,” Officer Wofferd said, “to help solve, yes this is definitely you these are your fingerprints, nobody else's."

Investigators who collect prints from a crime scene can search those prints for a match in the national database.

"We'll send it, and it'll let you know the packets been submitted," Officer Wofferd explained.

If a suspect has never committed a crime before, there will not be a match.

But there is no database to keep track of collected fingerprint evidence that has no match.

A spokesperson with the District Attorney's office said they do re-submit fingerprint evidence hoping for new leads, especially if they get a new tip.

Hamilton County has nearly 200 cold cases, and that does not include missing persons cases, which makes it difficult to supply the time and resources needed to regularly re-run old evidence.

But with each arrest and fingerprint, they have a higher chance of solving a case.

"It's very good because it goes all over the country,” Officer Wofferd said. “So if they have something anywhere, their fingerprints will be in that database."

At any given time, the DA's cold case unit is looking at nearly a dozen old cases.

Since its creation in 2014, the unit has solved 17 cases.