A third previously undisclosed person was involved in the infamous Kentucky Fried Chicken mass murders, a prosecutor said Monday as the trial of the first of two men charged with the slayings got under way.

Prosecutor Lisa Tanner said during opening statements of Romeo Pinkerton's capital murder trial that his knowledge of a third participant in the 1983 slayings of five people would confirm his presence at what became one of Texas' longest unsolved mass murder cases. DNA tests also showed Pinkerton's blood at the scene, she said.

Pinkerton's defense attorneys questioned the reliability of a key witness and the state's evidence-collection methods, but Tanner said the case is solid.

"This man, this defendant, is one of the people responsible for this crime," said Tanner, an assistant attorney general. "Science will not lie to you. Hold this man accountable for his actions. Ladies and gentlemen, it is time."

Tanner disclosed that Pinkerton, in a secretly recorded conversation with a fellow prison inmate, hinted he knew of that third person. The identity of that person remains unknown, she said.

"The third person is gone, dead, flown the coop," she said.

The existence of the person was confirmed when DNA tests showed one of the victims had been raped. Evidence of a rape also never had been disclosed, and Tanner prefaced her remarks by apologizing to several dozen relatives of the victims seated in the courtroom.

"There is something else at the crime scene," she said, then went into a description of the tests and evidence.

Pinkerton's lawyers suggested in opening statements that the evidence had been contaminated in an era when authorities weren't as sophisticated.

"A trial should be a search for the truth," defense attorney Jeff Haas said. "It's not going to be in this case because so many things are out there that can't be answered."

He raised questions about a man earlier charged with the slayings, saying the evidence didn't convince him the previous suspect wasn't involved. He also said the prison informant couldn't be trusted.

"This isn't the first time he's acting as a jailhouse snitch," Haas said of the prisoner who was wired and taped a conversation with Pinkerton. Haas said the prisoner made a deal to sweeten his own confinement and that the recording was difficult to understand.

"I'd be surprised you can make heads or tails of anything said," he said. "Nowhere on that tape Romeo Pinkerton said: I did it."

Pinkerton, 49, could be sentenced to death if convicted of capital murder. His cousin, Darnell Hartsfield, 46, also of Tyler, faces the same five charges when he goes to trial, probably next year.

The trial was moved to Bowie County in far northeast Texas because or publicity in the Kilgore area where the KFC was located, about 90 miles to the south. State District Judge J. Clay Gossett has said he hoped Pinkerton's trial will be done by Thanksgiving.

The victims were reported missing after assistant manager Mary Tyler's daughter arrived to pick her up but found the KFC empty. Investigators found blood on the floor, and a cash register tape showed about $2,000 had been taken from a cash box.

The next morning, the bodies of Tyler, 37, co-workers Opie Ann Hughes, 39; Joey Johnson and David Maxwell, both 20; and Monte Landers, 19, a friend of Johnson and Maxwell, were discovered in a field by an oilfield worker about 15 miles away. All had been shot in the head.

Pinkerton, wearing a suit, white shirt and tie, stood between his lawyers and with his hands clasped at his waist as Rusk County District Attorney Michael Jimerson read the indictment charging him with the five slayings Sept. 23, 1983.

Jimerson, at each mention of Pinkerton's name, looked at him. Gossett, after each count, asked Pinkerton how he pleaded.

"Not guilty," Pinkerton responded five times.

Tanner went through the long history of the case, acknowledging "tunnel vision" for much of the delay. She said investigators were sidetracked by an erroneous assumption that another man was responsible and initially were overwhelmed by the enormity of the case.

Detectives also were victims of bad luck, she said, like the failure of a technician who ruined nine of the 10 rolls of film shot by a detective at the crime scene. As a result, there are no photos of the scene, she said.

A broken fingernail found on the clothing of one of the victims led investigators to believe they had a good suspect, even though Pinkerton and Hartsfield had been identified as suspects early in the case. But years later, DNA testing showed the fingernail belonged to one of the victims, Tanner said.

"DNA wasn't a twinkle in anybody's eye in 1983," she said. "We're talking about the Dark Ages. Keep that in mind."

Records show Pinkerton, a convicted burglar who's been to prison at least five time, had been out of prison just two days when the crime occurred. His blood was found on a napkin. Blood from Hartsfield, who was arrested for aggravated robbery three days after the KFC slayings, was found on a box of cash register tapes.

Investigators believed at least some of their victims had put up a struggle before they were taken from the restaurant in a white van.

Tanner said Pinkerton told authorities he was in prison at the time, that his release had been delayed by Hurricane Alicia in 1983, had never been to the restaurant and had nothing to do with the slayings.

"The problem with that is there are records," Tanner said. "His alibi is a lie."