Ronald Tammen disappeared without a trace on April 19, 1953, from his dormitory at Miami University in Ohio. He was last seen investigating a disturbance outside his room, and his roommate found him missing later that night. His belongings, including his car and money, were all left behind.

Authorities have not found any evidence of foul play, nor has there been any sign of Tammen since his disappearance. There have been various theories about what could have happened to him, including amnesia, but nothing has been confirmed.

Some believe he was recruited by the CIA due to his psychology professor's possible involvement with the agency. However, there is no concrete evidence to support this theory. Tammen's case remains unsolved, but his family still hopes for answers.