A Brunswick man who was being towed behind a pontoon boat on Sebago Lake in Casco died Sunday afternoon, possibly as the result of some type of medical issue, authorities said.

Corey Wilcox, 37, started showing signs of medical distress, but when the pontoon boat slowed to help him, people on board the boat and another vessel tried unsuccessfully to administer lifesaving measures, according to a statement issued Sunday night by the Maine Warden Service.

Emergency medical personnel pronounced Wilcox dead at the scene. His body was taken to a funeral home in Casco, where the state’s chief medical examiner was expected to perform an autopsy.

Wilcox, who was not wearing a life jacket, was being towed on a tube behind a 22-foot Sun Tracker pontoon boat around 4:30 p.m. on New Place Cove near the Point Sebago resort. There were five people on the pontoon boat, which had been rented from Port Harbor Marine.

At the time, water conditions on Sebago Lake were “very rough,” the Maine Warden Service said. Several game wardens, members of the Cumberland County Sheriff’s Office and the Raymond Fire Department responded. The incident remains under investigation by the Maine Warden Service.