Could the answers to missing persons and cold cases be found in North Texas waters?
That's a question a group of volunteers and police may soon answer as divers search lakes around Fort Worth this week.
Adventures With Purpose, a sonar and recovery team based in Oregon, travels the country doing dives to help clean up waters but also to help solve cases.
On Tuesday, their group of divers partnered with the Fort Worth Police Department to search Lake Como.
As the volunteers dove beneath the surface, Rusty Arnold watched from the lake's bank.
His sister and two friends went missing from a Fort Worth mall just before Christmas 1974. The disappearance has haunted their families and the community for decades.
Operations like this latest effort keep him going.
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"There's hope," Arnold said. "When a car comes out of the water, there's no telling what's in it. You've got to turn that stone over."
Fort Worth police partnered with the volunteers so as divers discovered vehicles, police can check to see if they are linked to any unsolved cases.
"That's one of our big reasons for being involved here," said Fort Worth police spokesman Buddy Calzada. "We want to help our citizens solve some cases and have some closure to their cases."
In the last 18 months, Adventures With Purpose, said they've helped solve 12 cold cases.
"They say even when we don't find a lost loved one, we're still giving them answers because we're coming in and searching and showing them where their family is not," said Jared Leisek with Adventures With Purpose.
Arnold took the week off work to be at all of the organization's dives this week.
"Every time they pull a car up I want to see because there's a chance," Arnold said. "I just hope if not ours, somebody else's problem can be solved. Somebody else's mystery can be solved. There's a lot of missing persons out there."