SAN DIEGO -- A young man found dead in a hot tub at a hotel on Mission Bay this week following a night of partying in celebration of his 21st birthday drowned while intoxicated, authorities reported Thursday.

Michael Mayfield of Ocean Beach was found floating face-down in the spa at Paradise Point Resort about 5:30 a.m. Tuesday. Medics tried in vain to revive him before pronouncing him dead at the scene.

An autopsy determined that Mayfield drowned and that acute alcohol and cocaine intoxication contributed to his death, according to the county Medical Examiner's Office.

Mayfield and three of his friends had rented a room at the Vacation Road hotel the previous evening. They went into the hot tub about 5 a.m. and soaked for a time before all but Mayfield went back to their room.

About 15 minutes later, Mayfield's friends went back to check on him and found him floating lifelessly in the water, police said.

Mayfield turned 21 on Monday.