David Paul Talsma was 19 and a United States Marine when he left for a rock concert in Hammond, Indiana, on December 9, 1977, and never returned. His family searched for nearly two years before his remains were recovered on November 16, 1979 — what would have been his 21st birthday — buried in the crawl space beneath the Norwood Park Township home of John Wayne Gacy.

Investigators determined Gacy had lured Talsma to the house and strangled him with a ligature. David was cataloged by Gacy’s team as Body 13 and was positively identified by dental records and X-rays of his left arm. Talsma is one of at least 33 young men and boys linked to Gacy’s murders.

If anyone knew David, saw him in Hammond on December 9, 1977, or has information about his last day, please share what is known.