Investigators said a ski boat collided with the victims' WaveRunner watercraft on the lake just north of Castaic on Sunday at about 3:45 p.m. The teen was declared dead at the scene.
According to the Los Angeles County Sheriff's Department Parks Bureau, the personal watercraft turned into the path of the boat. Both victims were visiting from Russia. It appears they were friends with the driver of the boat, who tried to help them immediately after the crash.
"I saw one boat speeding out toward the launch area and a friend of his was holding another guy in the water with a jet ski all tore up -- handles broken, front cover broken," said witness Patrick Salem. "Apparently the boat ran over the jet ski and knocked both of them out."
The driver of the boat was not hurt. The victim who survived was airlifted to a hospital in critical condition. The sheriff's department said alcohol does not appear to be a factor in the crash.