John Walter Zuern was 21 when he left a hospital in London, Ontario without permission on June 14, 1975, and never returned to his family home in Guelph. His family reported him missing on July 21, 1975. At the time he was described as thin, about 5 feet 11 inches tall, 135–140 pounds, with blue eyes, long unkempt greyish-brown hair past his shoulders, and a pronounced limp.

John had been diagnosed with schizophrenia, and concern for his welfare followed his unexplained departure from care. In the summer of 1980 his brother reported seeing him in Toronto near Bloor Street West and Spadina Avenue, where it was believed he may have been living on the streets; that sighting is the last known report of him at age 26. The trail goes cold after 1980 and the Guelph Police Service continues to list the case as an outstanding missing person investigation.

If anyone has memories of John, saw him in Ontario in the late 1970s or 1980, or has information about his whereabouts, please come forward.