The case of a man found dead at a Gwinnett County apartment complex Monday evening has been ruled a suicide, police said.

The 60-year-old was found lying on the ground outside the complex on Oak Loch Trace off Steve Reynolds Boulevard with a gunshot wound, according to police. He was dead when officers arrived about 11 p.m.

A witness called 911 after hearing the gunshot, a Gwinnett police spokeswoman said.

Detectives launched a homicide investigation into the incident, but an autopsy determined the man’s gunshot wound was self-inflicted, police said Wednesday.