Crime Solvers Central
CSC
263 Cases Solved. Advancing justice for missing persons, unsolved homicides, unidentified and unclaimed remains.
Mark Nielsen missing person case profile photo

Mark Patrick Nielsen Missing Person Case

Last seen in San Luis Obispo County, California on Oct 10, 1994

Victim Details

Jan 24, 2026

Jan 24, 2026

Mark

Patrick Nielsen

72

41

5'8 inches

185 lbs

White

Male

Oct 10, 1994

San Luis Obispo County

California

San Luis Obispo County

San Luis Obispo County Sheriff's Departmen

805-781-4550

06/23/2026

Case Description

Any updates on this case? Let us know!
Mark Patrick Nielsen was 41 years old when he was last seen in San Luis Obispo County, California, on October 10, 1994. A resident of Los Osos, he has not been heard from since that day. His family officially reported him as a missing person on January 19, 1995, more than three months after his disappearance. There is limited information available regarding the circumstances of his case.

At the time he went missing, Nielsen was described as a White male with brown hair and blue eyes, st ...
MEMBER ACCESS

Continue reading the complete case summary

Unlock the full case narrative for Mark Patrick Nielsen, all available source links, additional videos, and member discussions.

Unlock Full Case Access — $3.97/month
Cancel anytime.
Already a member? Log in

Last Seen: Oct 10, 1994

Links to Additional Sources (4)

See any mistakes? Let us know!
  • Mark Patrick Nielsen - The Charley Project
  • 3258DMCA - Mark Patrick Nielsen - Doe Network
    • MEMBER ACCESS

    Unlock 2 additional sources

    View the complete collection of available reporting and reference links for this case.

    View All Case Sources — $3.97/month
    Cancel anytime.
    Already a member? Log in

    Latest News

    View All

    Forum Posts (1)

    I was reading through some old news articles about Mark Patrick Nielsen and noticed something intrig... ...Read More
    04/30/2023
    MEMBER ACCESS

    Join the discussion for Mark Patrick Nielsen

    Read full forum posts and contribute to this case discussion.

    Unlock forum access — $3.97/month
    Already a member? Log in

    Other Missing Cases from San Luis Obispo County, California

    Nicholas Deloss Marold missing person case in San Luis Obispo County, California

    Nicholas Deloss Marold

    Missing: Jun 23, 2017
    On June 23, 2017, 35-year-old Nicholas Deloss Marold of Arroyo Grande, California, was reported miss ...Read More
    Randall Gene Young missing person case in San Luis Obispo County, California

    Randall Gene Young

    Missing: Apr 28, 2010
    Randall Gene Young, a 51-year-old man from Morro Bay, was last seen on April 28, 2010, in San Luis O ...Read More