BOISE, Idaho — Police are investigating the death of a 61-year-old Boise man who went missing in August.

Mark Irwin’s body was found in his car in the Boise foothills under what police say are suspicious circumstances. The Ada County coroner announced Thursday that forensic testing confirmed the body was Irwin’s.

The date of Irwin’s death is listed as Aug. 26 and the manner of death is still pending. A police spokeswoman would not say exactly where or when the body was found.