Roger Mirro died of multiple crushing injuries Tuesday from being trapped in the compactor, the medical examiner's office found.
Authorities said they responded to Mirro's home on a report of a missing person at 9:30 p.m. Tuesday.
Mirro's wife told police she couldn't find her husband.
A neighbor told police Mirro had come to his apartment to ask for a key to the trash room in the lower-level parking garage, the Chicago Tribune reported.
Mirro had told the neighbor he thought he may have thrown his phone down the garbage chute.
When officers entered the garbage room, they found Mirro's body alongside the compactor, the Tribune reported.
The investigation is ongoing, but authorities said the incident was likely an accident.