Clayton, N.C. — Police seized two knives from the home of a Clayton man accused of killing his 4-year-old daughter last week, according to a search warrant released Tuesday.

John Patrick Violette is in custody in Washington, D.C., and is expected to be brought back to Johnston County on Wednesday to face a first-degree murder charge in the decapitation of his daughter, Katlin, police said.

Amber Violette returned home from work Friday afternoon to find her daughter dead and her husband missing. Neighbors said they saw John Violette speeding through the neighborhood and talking to himself earlier in the afternoon.

Police seized numerous items from the Violette home Friday afternoon as part of their investigation, including a serrated kitchen knife with dark red stains on it and a butcher knife.

Jeans, children's pajamas, a trash can, drywall and carpeting, all of which had dark red stains, a computer and miscellaneous documents also were taken from the home, according to the search warrant returned to the court after it was executed.

"We've prepared ourselves for (the possibility that) there may never be a suitable explanation for how something like this may have happened," Clayton Police Chief Glen Allen said Tuesday.

“I’ve been in law enforcement for 25 years. This is one of the worst cases I’ve ever been associated with, and I don’t understand it. I don’t know if I or anyone else will ever fully understand this type of thing,” he said.  "It's extremely puzzling to us as well as it is to ... everyone else."

Authorities tracked John Violette to a Washington, D.C., hotel, where they arrested him early Saturday. He was quoting Bible verses and screaming uncontrollably after his arrest, authorities said.

Clayton police have not talked with Violette yet, and investigators are checking to see if he had previous signs of mental illness, Allen said.

"That is part of the continuing investigation in this case," he said. “Several days into this investigation, we do not have a motive.”

District Attorney Susan Doyle said that a judge likely would order a mental evaluation once Violette has an attorney to represent him.