Paulo Dominguez was celebrating his 32nd birthday with his wife and friends and had been drinking before he started swimming across the river at DuBrava Beach in Guerneville around 5:45 p.m., according to the Sonoma County Sheriff's Department.
Dominguez started struggling and went underwater, Sgt. Michael Raasch said. About 20 of Dominguez's friends swam out and began to look for him. They found him 7-10 minutes later, Raasch said.
He was brought to shore where Raasch and Deputy Gary Thornton performed CPR until Monte Rio Fire Capt. Steve Baxman arrived. Baxman took over CPR and then Dominguez was taken by helicopter to the hospital, Raasch said.
Dominguez was pronounced dead at 11:55 p.m. Sunday, according to the coroner's office. An autopsy will be performed to determine cause of death.