SHASTA LAKE, Calif. -

Emergency crews are working to recover a drowned teenager on Shasta Lake and on Saturday the search continued.

The emergency call came in Friday around 10:30 a.m.  Sgt. Eric Magrini with the Shasta County Sheriff's Office said the 18 year-old Robinson Sok, from Oakland, was in the water with five other friends near a house boat on the McCloud Arm of the lake. Witnesses said Sok was last seen swimming in the middle of the channel and was apparently trying to help a friend. According to witnesses he went under and didn't come back up.

On Friday a helicopter, boats, firefighters, EMS crews, and Shasta County Sheriff's deputies responded.  The crews originally staged at Bridge Bay Road, however, with the help of Bridge Bay Resort, a houseboat served as a floating command center.

According to Sgt. Magrini, the crews were out all Friday afternoon and night as well as Saturday.The water is too deep for divers so the crews are using a remote-operated vehicle to comb the bottom of the lake.

The San Francisco Police Department also sent up high definition sonar equipment to help scour the bottom of the lake.

Officials say this is the first drowning on Shasta Lake this summer.