Michael Mansfield was 19 and home for winter break in Rolling Meadows, Illinois, when he disappeared on December 31, 1975. A Lincoln College student who worked at the campus radio station and shopped at local record stores, he told his mother after a 2:00 p.m. phone call that he was going to visit a friend in Arlington Heights and would return in about an hour. He left wearing a tan buckskin coat with a fleece collar, a brown print shirt, blue jeans or light brown pants, and white tennis shoes; he left his wallet at home and was never seen again.

Six days before his disappearance he had been scheduled to testify against his former college roommate, Russell Smrekar, in a burglary and petty theft case. Mansfield had initially hidden stolen items but later testified, which led to Smrekar’s expulsion from college. Decades later, in October 2011, Smrekar—then serving a long prison term for an unrelated 1976 double murder—made a deathbed confession saying he had killed Mansfield and another witness, Ruth Martin. He did not disclose where the remains were located. A 2017 search of a Will County property tied to Smrekar’s relatives turned up no human remains.

What can readers add about Michael’s last known movements or the friend in Arlington Heights he said he was visiting?