A volunteer diver died in a search for an Oakland teenager who was last seen in the water at Lake Shasta Friday, Shasta County sheriff's officials said.
The search for Robinson Sok, 18, started on Friday around 10:30 a.m. when the teen, who was on a houseboat with friends on the middle part of the McCloud Arm of the lake, attempted to help a friend who had been swimming.
The friend started to struggle and Sok apparently went in to retrieve him when he himself began to struggle and went under water and did not resurface, according to sheriff's officials.
Other friends then tried to find him, however they were unsuccessful and called authorities, officials said.
Because this part of the lake is deep, divers were not initially used and a San Francisco Police Department dive team's remotely operated vehicle and a sonar system were used. However Sok was not found by the end of the day.
On Saturday the search continued but the device became entangled on Saturday night and a salvage diver attempted to retrieve it, according to the sheriff's office.
A sheriff's office dive team member was also in the water as a safety diver, and had to pull the salvage diver out from the water.
Both were taken to hospitals where the salvage diver, identified as Ken Smith, died.
The safety diver, John Zufall, was later flown to Travis Air Force Base near Fairfield where he was placed in a decompression chamber.
Zufall has worked for the sheriff's office for 12 years and been on the dive team for about 10 years.
According to the sheriff's office, he is a certified advanced diver and was a diver in the U.S. Navy.
He is expected to survive.
A friend of Sok's posted on Facebook late Sunday night, "His family is asking if you could offer your time and help them continue their search for Rob. We just want to bring him home."