Oklahoma officials recently found two cars by mistake at the bottom of a lake that contained six skulls and skeletal remains, according to ABC News.

The remains sat 3 feet apart and under 12 feet of "murky" water.

Police also believe the cars might have gone on the water a year-and-a-half apart, and 40 years ago.

"It's just so crazy," said Oklahoma Highway Patrol spokeswoman Betsy Randolph to ABCNews.com.

Oklahoma Highway Patrol's lake patrol division was recently testing new sonar equipment in Foss Lake in Custer County, Okla. It was there that they found unusual echoes that "indicated the presence of large, metal objects under the water" according to ABC News.

Just a few feet away, police found the second car with more skeletal remains inside. They've recovered six skulls with matching bones, according to police.

"Our guys just naturally assumed this may have been a stolen car pushed off into the lake. Sometimes that happens," Randolph said. "As soon as they pulled up the first vehicle, they found a femur bone in the driver's seat."

Investigators believe they could have leads on the identities of the people found in the cars, which would solve cold cases from 40 years ago.

Randolph isn't sure how far from the shore the cars were but said there is a ramp at the edge of the lake for people to back boats into the water.

"This very well may be the car with three missing teens from Sayre in 1970," said Custer County Sheriff Bruce Peoples to ABC News affiliate KOCO-TV. "We have some indication that the other vehicle is one that was reported missing in 1969."

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