DETROIT (AP) — Police are investigating the death of a 21-year-old man who apparently fell down an elevator shaft while playing hide-and-seek with friends in a vacant Detroit building.

Wayne County Medical Examiner’s Office spokesman Keith Owens identified the victim as 21-year-old Jonathan Mazgai of Taylor. The official cause of death has not yet been determined.

Police say the group was on the building’s ninth floor early Saturday. Mazgai’s friends left when they couldn’t find him, but they returned later to search for him. They called 911 after finding his body in the shaft on the building’s first floor.

The site where the incident occurred was formerly Grand Trunk Warehouse & Cold Storage. The facility closed in 2002.

Detroit police Cmdr. Charles Mahone said a city crew went to the building Monday to ensure it was properly secure.