KNOXVILLE, Tenn. (WVLT)--The Knox County Sheriff's Office and Knoxville Police work hard to solve cold cases.

One man faces first degree murder charges for killing his mom 25 years ago after a break in the case in April.

Today, special recognition for the team that made the arrest.

Police found Bobbie Lou Hill stabbed and beaten to death in September 1986.

That day, her son Billy Ray Hill, Junior, drove away in his mom's sports car.

It wasn't until 25 years later a witness came forward connecting billy to his mother's killing.

Bobbie's Co-worker Brenda Senseny says, "It does give you a sense of peace to know she hasn't been forgotten."

Wednesday the entire cold case unit got honored for its work.

Assistant Cold Case Unit Chief David Davenport says, "That's what we thought about Billy Hill. He didn't need to be out one more day after we got the indictment that he had killed his mother."

But there are other unsolved murders.

More than 200 dating back to the late 60's.

Davenport says, "There's somebody out there walking around that has killed someone who we're working on and actively pursuing right now."

Some of the murderers may already be behind bars.

TBI doesn't do the sophisticated DNA testing so the unit is pursuing a grant.

For now investigators are putting in the leg work.

Davenport says, "We're working on these cases every day. We were out yesterday. Every day of the week. Sometimes every night of the week."

Some relatives may be dead, others moved out of state.

Investigators believe someone knows something.

Investigator Dorothy Barnes says, "If they know anything. If the name sounds familiar something in past. Time went by they're not afraid now."

If you know anything call Knoxville Police or Knox County Sheriff's Office.