"We've asked for specialized equipment that will show us a picture what's underneath the earth surface," Midwest City Police Chief Brandon Clabes said.
It's a ground penetrating radar that uses a sonar.
"It's time-consuming very painstaking process typically they go door by foot so we may be out here days, could be up to weeks before we clear this scene," Clabes says.
They're trying to find something, anything that could lead them to 8 year-old Kirsten.
"We've already found some animal parts in the backyard, but we knew from family members there would be some pets in backyard," Clabes said.
The equipment they're using is from OSBI.
It helped them crack a case in Shawnee.
"We're able to assist in locating and identifying human remains," Beth Green with OSBI said.
"It enables us not only to look at what's on the surface but also see what's below the surface," Green said.
That same sonar equipment is looking for any clues to the 18-year-old case.
"It doesn't give us pictures, it gives us images so we see lines and what we're looking for is some difference in the surrounding area," Green describes.
A small piece that could help investigators.
"Our hopes are if there's anything buried we would be able to find it," Clabes said.
Anthony Palma was taken to Oklahoma County jail Tuesday night, he remains under suicide watch.