Fresh eyes on a 1993 Missouri cold case caught a suspect making incriminating comments when police left a room during a 2015 interrogation.
When detectives walked away and closed the door, Loril Harp was seen talking to himself and chatting on the phone, saying things like, "I'm not under arrest, but I probably will be before I leave here."
At the time, he was being questioned about the shooting death of Steven Weltig, a 40-year-old liquor store owner in Arnold, Missouri.
Cpl. Brett Ackermann and Det. Corporal Josh Wineinger picked the case back up in 2020, including a review of several hours of the 2015 interview.
That's when they noticed Harp talking to himself. In one of seven videos, which were obtained and reviewed by Fox News Digital via a public records request, Harp curses out a woman.
In another, he's yelling at himself, saying he didn't kill Weltig. He was constantly twitching, shuffling in his chair, tapping his feet.
"Watching that dead time helped us," Wineinger told FOX 2 St. Louis during an on-camera interview. "I was 100 percent convinced at that point."
Ackermann pointed out a phone call Harp made when no one was in the room and paraphrased the conversation.
"He was on the phone with someone saying, ‘I’m going to jail.' Stuff that would indicate he was guilty of this," Ackermann said.
LISTEN TO HARP ON THE AUDIO TAPE DURING 2020 INTERROGATION
That was enough for detectives to bring Harp back for questioning in 2020 when he was 68 and in failing health.
He dodged questions, played dumb and was evasive for more than three hours of a 3½-hour interview, which was recorded on audiotape and shared with Fox News Digital through a public records request.
Toward the end of the interview, Ackermann told Harp they knew he was in the shop at the time of Weltig's death, and they knew a gun went off. They needed to know how.
"How did it happen?" Ackermann asked Harp. "How did it happen that (Weltig) got a bullet hole in his head? And you're the only other person there, Loril?"
He denied shooting Weltig twice and claimed Weltig charged at him with a gun. Harp began to describe the altercation and then momentarily paused.
"Keep going," Ackermann said.
"I grabbed his hand and hit him until he dropped the gun. And then I hit him again, and then I took off out the door," Harp said. "I hurt him. I know I hurt him. Like I said, I fight. I hit him f------ hard. But I didn't shoot him."
The shooter used the store's side door to make his getaway, so the detectives' ears perked up when Harp mentioned the side door.
They asked him what he did when he got home.
"I showered, I had a bunch of blood on me," Harp told the Arnold detectives.
WATCH HARP MAKE THE PHONE CALL
One of the detectives repeated what he had said. "You had blood on you?" the detective asked.
"I must have if I shot him. Or he shot me," Harp said.
"You weren't shot," one of the detectives replied.
Harp tried to backtrack and said the blood was from a fist fight. But it was too late. The detectives had him.
He was arrested Sept. 30, 2020, and charged with first-degree murder and armed criminal action.
At the end of the interview, Wineinger asked Harp, "Doesn't that feel better? After 27 years, to know that you don't have to worry for the rest of your life with this hanging over your head."
He died a year later at the age of 69 from an undisclosed illness.
Fox News Digital's Jasmine Baehr contributed to this report.