ROYSE CITY, Texas (CBSDFW.COM) — This week, multiple federal, state and local law enforcement agencies are in Royse City trying to track down a man they believe murdered his estranged fiance nearly three years ago.

In March of 2017, then 35-year-old Lori Hannah was found dead in her in Ward, Arkansas home. And after all this time, Hannah’s family is still waiting for closure.

Lori Hannah

Deputy Jeremy Hammons has been the lead on this investigation since the beginning.

“I desperately want to solve it,” Hammons said.

He believes Hannah was murdered by her estranged fiance, 41-year-old Brian Keith Freeman.

Brian Keith Freeman

“He had sent some text messages to family members the early morning hours of March 23, 2017, saying he had killed his estranged fiance,” he said. “I think that he met with her that evening and I think things didn’t go the way he intended for it to, and he reacted spontaneously to that and then once he realized what he had done, he fled the area.”

Freeman’s last phone call was made in rural Royse City, where authorities later found his pickup truck abandoned.

“The area was searched right after the truck was found,” Hammons said. “Based on longevity, how long this case has been going on, we had to go back to ground zero.”

This week, “Operation Backtrack” was launched and Deputy Brandon Filla brought CBS 11’s Erin Jones inside the mobile command center.

“Right here is a computer screen with our grid coordinates and our plotted areas,” Filla said. “Each of those 20 acres was basically like you’d mow your lawn… just back and forth search.”

Cadaver dogs are also assisting, trying to detect any signs of human remains.

“As we get to the conclusion of this mission here this week, we still haven’t recovered anything of value,” Filla said.

He said if Freeman is dead, he’s not in the area.

“So, that’s going to be my next step is finding out how he got away from this area. I think Lori‘s mother put it best to me one time when she said that you know Keith is out there breathing the air that he took away from her daughter,” Hammons said. “We’re going to find him.”

Anyone with information on Freeman is asked to contact police immediately.

Erin Jones