The San Francisco Medical Examiner's Office this morning said it was 46-year-old Ross Ehlinger who died on Sunday during the city's popular Escape From Alcatraz triathlon, marking the first death in the history of the annual event.

SF Weekly reports that the Austin resident died less than a minute after he jumped into the chilly water; he was pulled from the Bay immediately and paramedics performed CPR, but were unable to revive him.

Medical authorities told SF Weekly this morning the death is still under investigation and they have "no idea what happened to him yet."

The race includes a 1.5-mile swim from the site of the former federal prison followed by an 18-mile bike ride and an 8-mile run through San Francisco.