PORT ORCHARD - The Kitsap County coroner's office says there was no trauma or other obvious cause of death for a young Kingston man who died aboard a state ferry at Bainbridge Island.

The office said Thursday the final autopsy report is awaiting blood toxicology tests.

The 24-year-old man, Nicholas Thompson, was riding the 2:05 p.m. sailing of the ferry Tacoma from Seattle to Bainbridge Island on Tuesday. The boat docked at Bainbridge and unloaded cars and passengers.

During a routine security sweep, ferry workers found Thompson having trouble breathing, said Washington State Ferries spokeswoman Marta Coursey. The ferry's captain performed CPR on the man, but couldn't keep him alive until Bainbridge Island Fire Department medics arrived, Coursey said.

"It was very unfortunate," Coursey said. "Our condolences go out to our crew and our captain because they were very valiant in their effort, and to the family of this gentleman."

The Kitsap Sun, a media partner of KOMO News, contributed to this report.