RICHARDSON, Texas -- The search for Sherin Mathews took many forms on Tuesday.
On foot, officers in grid-like fashion walked up and down fields paying close attention to large mounds and nearby bodies of water.
"What you're seeing now a week into it are some specific area searches," said Sgt. Kevin Perlich.
But Tuesday also saw a new element of searching. From up high, drone technology was employed by the North Texas Unmanned Aerial Systems (UAS) Response Team.
Jamie Moore is the Emergency Management Director of Johnson County. He said that the relatively new team was out there Tuesday with four members using two drones.
"It gives you a much better perspective of what the terrain looks like, what the ground looks like," he said.
Moore can't talk about the search because it's an open investigation. He said missing person cases require incredible patience and concentration for pilots and the people tasked with monitoring what the drone's cameras are showing.
WFAA witnessed that technology first-hand when we followed the group earlier this year for a story.
"You can see car tracks for example that might have driven through dirt," Moore said. "You can see where dirt may have been disturbed, and you can see articles of clothing."
Once they find something, Moore says people on the ground search that location. An urban place like Richardson can make that challenging.
"You have to be more detailed," he said. "You find a lot more human existence, you find a lot of trash blown off into a field."
We did notice searchers finding items worthy of being put into bags and placed into their vehicles. It's unclear what they found and why it was important. But these searches are about two things: finding Mathews or finding what happened to her.