The search for a missing Henryetta man continues.
Crews searched for miles Thursday around Jim Hall Lake looking for Duane Qualls, who was last seen Tuesday.
Search crews are not giving up hope of finding Qualls.
They plan to come back to the area once the wind calms down in a few days, to make sure Qualls isn't in the lake.
Crews have searched more than 20 square miles from the air, and more than 12 square miles on the ground. And so far, they've found nothing.
"Absolutely nothing," said Tim Craighton, Okmulgee County Emergency Management director.
The search for 49-year-old Qualls began Tuesday.
The Okmulgee County Sheriff's Office is concerned for his health. They said he has paranoid schizophrenia and diabetes.
A handful of people who live nearby told investigators they heard someone yelling after dark on Tuesday.
"When they would try and respond with him didn't respond back to them," Craighton said.
Craighton is working alongside several agencies in rough terrain to cover as much land as possible.
An armored Humvee is making a difference in how efficiently crews can search the area.
"We've been able to maneuver back into some places that the UTVs didn't or wouldn't go. And we've been able to drop boots on the ground," said Henryetta Police Chief Steve Norman. "Our troops have done a good job of walking through it, making sure there's nothing there."
Investigators said this is not the first time Qualls has disappeared for a couple days.
Earlier this week, the sheriff's office did find his vehicle on the other side of the lake in a parking area.
If you have any information on Qualls' possible whereabouts, call the Okmulgee County Sheriff's Office at 918-756-4311.