Platteville police are investigating the death of a man who died early Monday morning.

Police received a report of a man who had passed out and was not breathing at 47 N. Second St. around 1 a.m.

When officers responded, they found that the person who called in the report had started CPR.

The man was taken by Platteville EMS to Southwest Health Center, where he was pronounced dead.

According to police, an autopsy was performed, and the cause of death is pending toxicology results.