RICHMOND, Va. (AP) — Convicted DC snipers Lee Boyd Malvo and John Allen Muhammad were supposed to have had help carrying out their deadly attacks, and they may have been involved in more shootings than authorities suspected, according to an interview with actor William Shatner that airs Thursday.

In a telephone call from a southwest Virginia prison, Malvo told Shatner two others planned to help with the killings but they backed out and at least one was killed.

Also, Neil Blumberg, a psychiatrist who worked with Malvo, said he confessed to at least 42 shootings during the killing spree that culminated with 13 shootings and 10 deaths over a three-week span in 2002 that terrorized the Washington region.

But when asked about his psychiatrist’s claims that he and Muhammad had co-conspirators, Malvo originally denies it. Once pressured, he says someone in Arizona helped them get weapons and explosives, and a man in New York was supposed to help them get out of the country “when it’s all said and done.” He said both later backed out of plans to help with the shootings.

“There was supposed to be three to four snipers with silenced weapons,” said Malvo, who was 17 at the time of the shootings. “In this way we could do a lot more damage along the entire Eastern Seaboard.”

When asked about the number of shootings, Malvo rattles off states where he claims he and Muhammad shot people but doesn’t give an exact number.

The one-hour “Confessions of the DC Sniper with William Shatner: An Aftermath Special” premieres at 10 p.m. Thursday on A&E.

Previously, Malvo and Muhammad had been linked to as many as 27 shootings resulting in 17 deaths in 10 states and the District of Columbia.

Malvo’s statements have been inconsistent in the past, and authorities have cast doubt on some of his reported confessions since he was sentenced to life in prison. Muhammad was executed in Virginia last year.

Malvo’s lawyer during his trial, Timothy Sullivan, did not immediately return a phone call Thursday seeking comment.

Blumberg said Malvo told him Muhammad made him shoot two of the co-conspirators once they backed out of the plan. Malvo told Shatner only one of the men was killed, and that Muhammad did it.

Blumberg also said Malvo told him there was a third co-conspirator who was supposed to have joined them in Washington but did not. Malvo does not mention that person during the interview with Shatner.

The sniper-style attacks all but paralyzed the nation’s capitol, as people were shot at random while going about their everyday life — pumping gas, buying groceries, and for one young boy, as he went to school. The shooters used a high-powered rifle, firing from the trunk of a modified Chevy Caprice until they were tracked down at a Maryland rest stop.

Authorities involved with the massive hunt and prosecution of the pair are reluctant to say how many shootings they may have been involved in as they drove across the country to the nation’s capitol.

An FBI spokeswoman did not immediately return a call seeking comment Thursday.

Before Muhammad was executed last November, the prosecutor who put him on death row said it may be impossible to ever know how many were killed. Malvo has only confessed to authorities in jurisdictions that promised not to prosecute him.

“I don’t know that you can trust anything Malvo says,” Prince William Commonwealth’s Attorney Paul Ebert said.

Speaking on ABC’s “Good Morning America” on Thursday, Shatner said he was fascinated by Malvo’s turnabout, “the fact that remorse creeps into his life.”

“He was a kid who was brainwashed. He was a malleable teenager and lacking love in his life,” Shatner said. “John Muhammad supplies the love and influences him to become a killer, and he becomes a cold-blooded killer at the age of 17. Now he’s in jail and now he begins the turmoil in his mind.”

Malvo, now 25, said he has forgiven Muhammad, who at trial he accused of turning him into a “monster.”

“This is going to be surprising, but I’ve had to forgive him in the same way in which I’ve had to, over time, gradually forgive myself,” Malvo said. “…Every day I get up, somebody’s wife, child, husband is not going to come home tonight. There is nothing that I can say or ever do that will ever change that fact.

“That is my constant reminder. Someone else cannot breathe for you. You can allow someone else to think for you, and when you do these are the consequences.”

Malvo, who lives in segregation at a maximum security prison, said he is filled with “hope and dread” for his future.

“It’s a little bit of both,” he said. “It’s hope and dread because everything has to be repaid.”