Rangers with Georgia's Dept. of Natural Resources were back out on Lake Oconee on Tuesday.
They used a remote-controlled underwater camera to search under docks behind Shirley and Russell Dermond's home.
Ranger Grant Matherly watched his computer screen while he controlled the camera's movements.
"We use it to look for bodies, boats, vehicles - whatever of interest we need to find at the time," said Matherly.
They are searching for 87-year-old Shirley Dermond and the head of her 88-year-old husband Russell.
Police discovered Russell Dermond's body inside the couple's home in the Reynolds Plantation's Great Waters Community last Tuesday.
They believe Shirley Dermond was abducted. A week later still there are no clues and no motive.
"If there is something down here, you want to be able to find it and give that family some closure that they are looking for," said Ranger Richard Tanner.
The DNR used sonar equipment to search the cove behind the Dermonds' home and other parts of the lake.
"We have scanned a good portion of the lake. We have searched from the victims' house all the way down to the Wallace Dam, which is a good five miles away from the area," said Tanner.
At this time, they don't have any reason to believe Shirley Dermond or her husband's head are in Lake Oconee.
"It's kind of a guessing game right now since we don't really know if the victim is in here or not, or where it could have gone from here," said Tanner.
If there is something in the lake, what the sonar does not pick up, the robot will.
"The controls on this are very sensitive. It's difficult sometimes to stay where you want to stay," said Matherly. "It's a lot of moving back and forth to be able to look at what you want to look at."
It even gives clear images in the murky water.
"The glass over the camera acts as a lens that helps clear it up a little bit and we have two bright halogen lights on the front of it," said Tanner.
The FBI is offering a reward of up to $20,000 for information leading to the location of Shirley Wilcox Dermond and/or the arrest of the individual(s) responsible for her disappearance.
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