Mark O’Neill was 45 when he disappeared from Harbor Beach, Michigan, on October 16, 1988. He was last seen in the Harbor Beach area, and the circumstances of his disappearance remain unclear.

There are very few details available about what happened before he vanished, and investigators report little to no physical evidence has emerged. His case is logged in the National Missing and Unidentified Persons System (NamUs), and authorities continue to seek information.

If anyone has information about Mark’s movements in Harbor Beach around October 16, 1988, or remembers seeing him before he went missing, please contact the investigators handling his case.