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Mark Bonner Missing Person Case

Last seen in Boulder, Colorado on Mar 20, 1978

Victim Details

Aug 05, 2014

Jul 26, 2022

Mark

Bonner

71

23

75 inches

150 lbs

White / Caucasian

Male

Mar 20, 1978

Boulder

Colorado

Boulder County

23406

Boulder County Sheriff's Office

Boulder

Colorado

Boulder County

80301

Steven Ainsworth

Detective

5600 Flatiron Parkway, Colorado

3034413600

County

Law Enforcement

https://www.bouldercounty.org/safety/sheriff/

78-3741

Boulder County Sheriff's Office

Blond/Strawberry

Blue

Blue

07/16/2026


Area Last Seen:

Case Description

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In the quiet town of Boulder, Colorado, a young man named Mark Allen Bonner seemingly vanished without a trace, leaving behind a mystery that has endured for decades. On March 20, 1978, the 23-year-old was last seen, and the circumstances surrounding his disappearance have remained frustratingly vague. At the time, Bonner was house-sitting at a residence on Neva Road, located north of Boulder. Details about his last known movements are scarce, with no witnesses to his departure or any indication ...
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Last Seen: Mar 20, 1978

Links to Additional Sources (7)

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  • Mark Bonner - The Charley Project
  • Mark Allen Bonner- A Cold Missing Persons Case in Colorado - Reddit
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    Forum Posts (2)

    Does anyone have information on Mark Bonner’s family or friends at the time he disappeared? I've b... ...Read More
    12/17/2024
    Does anyone have any info on the sighting of Mark Bonner by the older man who reportedly saw him on ... ...Read More
    04/10/2024
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