(CBS) — An autopsy Wednesday identified the body of a man that washed up on a beach in Whiting, Indiana as the last missing victim of the season’s first fatal boating accident.

According to the Lake County Coroner, the body belongs to 30-year-old Orest Sopka, whose 33-foot boat capsized about six miles offshore on May 31, as he and three others were returning to Chicago from a trip to New Buffalo, Michigan.

A man walking his dog found the body Monday night.

Based on information from the lone survivor, authorities believe an electrical malfunction on the boat sparked a fire, and knocked out the boat’s engine and radio. The four passengers ended up in the water after dark.

A fisherman brought the survivor to shore the next morning, after he was found floating on several life jackets.

Ashley Haws, 26, died at a Chicago hospital after she was pulled from the water about two hours later. The body of another female passenger, 26-year-old Megan Blenner, was found near Navy Pier a month later.

The boat itself has not been found.