Convicted D.C. sniper Lee Boyd Malvo has told actor William Shatner that two others planned to participate in the terror attacks but backed out.

The revelation comes in a prison interview for the premier of "Confessions of the D.C. Sniper with William Shatner; An Aftermath Special" on A&E television. Malvo, now 25, says the two people who backed out were shot, and one was killed. Malvo's accomplice, John Allen Muhammad, was executed last year.

The special is part of Shatner's new series, "Aftermath with William Shatner," which premieres Monday on BIO and looks at what happens "when people are tragically or infamously transformed from unknown citizens into household names overnight."

- Scott McCabe