Trooper George Hoyle said the Lake Patrol Division used the equipment in the specific area of Foss Lake because the parks department wanted to see if a boat ramp could be extended, KFOR-TV in Oklahoma City reported. He said the troopers were not surprised to find old cars on the lake bottom but did not expect to solve two decades-old missing persons cases.
The cars and the human remains were found Tuesday.
"The fact that they found a couple of cars is not unusual but what is unusual, obviously, is that there were remains in those cars," Lt. Greg Giles said.
One of the cars, a blue 1969 Chevrolet Camaro, appears to match the one driven by Jimmy Allen Williams, 16, of Sayre, who told his parents he was going to a football game in Elk City on Nov. 20, 1970, with two friends, Thomas Michael Rios and Leah Gail Johnson, both 18. The three teens have not been seen since.
The other car, a 1950s Chevrolet, also held three skeletons. Investigators say the car may hold the remains of three people last seen buying beer in the small town of Canute.
Investigators say identifying the skeletons could take weeks or even years.
"We do hope this gives closure to some families in finding the remains, so they can have some rest," Hoyle told the Daily Elk Citian.
Foss Lake, the largest body of water in western Oklahoma, was created by the U.S. Bureau of Reclamation and completed in 1961.