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DENVER (KDVR) — There are hundreds of unsolved homicide cases, long-term missing person cases, and unidentified remains cases in Colorado where at least three years have passed since the crime happened.

The Colorado cold case task force created a list of those cases dating back to 1970. The Problem Solvers are working to highlight cold cases in our state.

What happened to Mark Bonner?

Mark Bonner was last seen in Boulder on March 20, 1978. He has not been seen since then.

Bonner is described as:

  • White
  • 6 feet 3 inches tall
  • 150 pounds
  • Blue eyes
  • Blond/strawberry blond hair
Mark Bonner in 1978

Bonner would be 68-years-old in 2022.

Police said foul play is suspected in Bonner’s disappearance.

If you have any information, please contact the Boulder County Sheriff’s Office at 303-441-3600.

Here are some of the other cases we’ve highlighted:

If you ever have a cold case you would like us to feature, please fill out this form:

The National Missing and Unidentified Persons System shows there are currently 21,556 open missing persons cases in the United States and over 300 in Colorado.