Lieutenant Hastings said the police had no reason to think Ms. Pressly had been singled out before the evening her assailant entered her rented cottage-style home in the affluent Pulaski Heights neighborhood.

Image Anne Pressly, a newswoman in Little Rock, Ark., died five days after she was attacked. Credit... KATV Television

“He was not stalking her,” he said in an interview. “We don’t know for sure, but we think the motive is going to be robbery. I think he saw an opportunity and took advantage of it.”

The police declined to say whether Ms. Pressly had been raped.

For weeks police agencies across Arkansas and beyond had supplied detectives here with names and DNA samples of possible suspects, hoping that the material would match evidence taken from Ms. Pressly’s home.

None of the forensic specimens were a match until Wednesday. “This time it came back positive,” Lieutenant Hastings said, explaining only that scientists at the Arkansas State Crime Laboratory here tied forensic material from Marianna, including DNA, to evidence collected from Ms. Pressly’s home.

Police officials disclosed on Friday that detectives from Little Rock had interviewed Mr. Vance on Tuesday at police headquarters in Marianna, about 100 miles east of here, after learning he had been questioned by officers there in a rape near his home on April 21. A warrant has been issued for Mr. Vance’s arrest in the rape case, said Detective Sgt. Carl D. McCree of the Marianna police.