Gaines Blevins said his brother-in-law said "he'd traded his soul for a new truck and that he murdered two people," the affidavit says. "He said they were out shooting target practice and he couldn't trust them so he killed them before they could kill him. He said he couldn't trust anyone anymore; everyone was out to get him."

Laura Blevins told her brother that if what he was saying was true, "he needed to turn hisself in," it adds.

But Routh set off again.

At about 8 p.m., police caught up with him near his home in Lancaster, about 15 miles south of Dallas, and took him into custody.

The motive for the killings was unclear

Routh "is the only one that knows," Erath County Sheriff's Capt. Jason Upshaw told reporters on Sunday. "I don't know that we'll ever know."