SACRAMENTO, Calif. (KGO) -- It is a plane crash mystery that has sat cold for decades, but the case may have just been cracked wide open.
Jeff Riley and Tyler Atkinson say they have spotted the wreckage of a 1965 plane crash at Folsom Lake, using their underwater sonar technology.
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The Single Springs-based researchers were recently testing their advanced surveying equipment when they saw the plane's tail and propeller that matched the description of the same downed Piper Comanche 250 aircraft.
"I saw something that was not normal," said Atkinson.
""He sees something on the bottom like this that looks man-made," added John Timplin, President of Seaforce Systems. "That's when we decide okay there's definitely something down there and maybe its the plane."
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It was New Years Day in 1965 when that plane crashed near the Folsom Dam, just outside of Sacramento, after a mid-air collision. The bodies of three people onboard were never found. The body of the pilot was the only one discovered. Now, this new technology has been updated, with the Seaforce Systems' images showing a fully-intact plane.
Depleted water levels at Folsom Lake also made it easier for the sonar equipment to get a clearer image.
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"I think it's definitely a rewarding prospect to offer some sort of closure," said Riley.
In 2014, crews looked once again for the plane wreckage, but came up empty.
The brother of one of the victims onboard, Frank Wilcox, had never stopped looking for the plane, or his brother's remains. But Wilcox passed away two years ago, never to learn of this new discovery.
According to the Placer County Sheriff's Office, it has no current plans to remove the plane.
CNN contributed to this report.