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Crime Solvers Central
302 Cases Solved. Advancing justice for missing persons, unsolved homicides, unidentified and unclaimed remains.

Case Description

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Summary based on the NamUs case record (MP19186) and 4 other sources
Mark William Kotlarz, aged 26, was last seen on July 5, 1991, near the northeast part of Vail Lake in Riverside County, California. He disappeared under unknown circumstances and has not been heard from since. At the time of his disappearance, Mark stood 5'9" tall, weighed 150 pounds, and had brown hair and green eyes. He also had a distinctive 12-inch scar on his right arm from a previous fracture and wore glasses. His case is classified as endangered missing, and despite the passage of time, no significant leads have emerged to explain his disappearance.

Authorities have continued their efforts, with dental and DNA records available to aid in identification, but so far, no concrete answers have been found. The Riverside County Sheriff's Department is overseeing the investigation, urging anyone with information to come forward. Mark’s disappearance remains a mystery, and his family still seeks closure.

Last Seen: Jul 5, 1991

Possible Unidentified Matches (10)

Unidentified remains cases whose details are consistent with this person, ranked by how closely they compare. Fields that are unknown in either case are left out of the score.

82%Moderate
John Doe — Corona, California
UP7106 • Found Jul 23, 1991
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Sex ✓Male
Age 85%Est. 20–45 vs 26
Race 100%White
Location 91%43 mi away, same county
TimingFound 3 weeks after last seen
Height 100%5'8" vs 5'9"
Weight 100%141 lb vs 150 lb
Hair 100%Brown vs Brown
81%Moderate
John Doe — Coachella, California
UP7041 • Found Mar 21, 1994
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Sex ✓Male
Age 85%Est. 20–40 vs 26 when missing
Race 100%White
Location 90%48 mi away, same county
TimingFound 3 years after last seen
Height 100%5'9" vs 5'9"
Weight 100%160 lb vs 150 lb
Hair 100%Brown vs Brown
80%Moderate
John Doe — San Diego, California
UP56918 • Found Oct 2, 1997
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Sex ✓Male
Age 100%Est. 25–40 vs 26 when missing
Race 100%White
Location 94%34 mi away, same state
TimingFound 6 years after last seen
Height 100%5'6"–5'10" vs 5'9"
80%Moderate
John Doe — San Diego, California
UP57048 • Found Oct 23, 1996
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Sex ✓Male
Age 100%Est. 28–35 vs 26 when missing
Race 100%White
Location 89%50 mi away, same state
TimingFound 5 years after last seen
Height 100%5'6"–5'9" vs 5'9"
Hair 100%Brown vs Brown
80%Moderate
John Doe — Corona, California
UP7039 • Found Nov 1, 1995
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Sex ✓Male
Age 100%Est. 25–35 vs 26 when missing
Race 100%White
Location 91%43 mi away, same county
TimingFound 4 years after last seen
Height 100%5'8" vs 5'9"
Hair 60%Black vs Brown
80%Moderate
John Doe — Pinyon Pines, California
UP7046 • Found Nov 13, 1994
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Sex ✓Male
Age 100%Est. 20–30 vs 26 when missing
Race 100%White
Location 95%31 mi away, same county
TimingFound 3 years after last seen
Height 84%5'11" vs 5'9"
Weight 87%175 lb vs 150 lb
80%Moderate
John Doe — Temecula, California
UP7875 • Found Feb 2, 1994
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Sex ✓Male
Age 85%Est. 20–40 vs 26 when missing
Race 100%White
Location 100%10 mi away, same county
TimingFound 3 years after last seen
Height 100%5'9" vs 5'9"
80%Moderate
John Doe — Hemet, California
UP7067 • Found Mar 19, 1992
View case
Sex ✓Male
Age 85%Est. 25–45 vs 26
Race 100%White
Location 98%18 mi away, same county
TimingFound 8 months after last seen
Height 84%5'7" vs 5'9"
Hair 100%Brown vs Brown
79%Possible
John Doe — Salton City, California
UP15289 • Found Jul 26, 1997
View case
Sex ✓Male
Age 100%Est. 30–45 vs 26 when missing
Race 100%White
Location 86%60 mi away, same state
TimingFound 6 years after last seen
Height 100%5'10" vs 5'9"
Weight 93%170 lb vs 150 lb
79%Possible
John Doe — Spring Valley, California
UP57374 • Found Dec 28, 1995
View case
Sex ✓Male
Age 100%Est. 18–32 vs 26 when missing
Race 100%White
Location 88%53 mi away, same state
TimingFound 4 years after last seen
Height 100%5'6"–5'9" vs 5'9"

These comparisons are generated automatically from public NamUs case data and are not confirmed identifications. Only DNA, dental or fingerprint comparison by investigators can confirm an identity. If you believe two cases are connected, contact the agency handling the unidentified case.