Divers have recovered the body of 21-year-old Phillip Stevenson, who drowned in Lake Berryessa Sunday during a fishing trip with friends.

Stevenson, 21, of Oakland, was swimming in an area of the lake known as Party Point, east of Markley Cove, when his friends saw him floundering in the water at about 4:25 p.m., Napa County Sheriffs Lt. Tracey Stuart said.

Friends reportedly swam out to rescue Stevenson, but were unable to reach him before he went under.

Stevenson’s body was recovered by a team of four divers from the Napa County Sheriffs Department on Monday morning. He was found submerged in water near Party Point, where he was last seen by witnesses.

Divers found Stevenson’s body after one hour of searching, according to Stuart. The diving team did not respond to the scene on Sunday because the accident occurred too late, she said.

Investigators will conduct an autopsy to determine the official cause of death. Stuart said alcohol is not believed to be involved.