Malvo, 27, told The Washington Post he now comprehends the grief and fear he and accomplice John Allen Muhammad caused during the 21 days in October 2002 when the two shot 13 unsuspecting strangers, killing 10 of them.
"I was a monster," Malvo said. "If you look up the definition, that's what a monster is. I was a ghoul. I was a thief. I stole people's lives. I did someone else's bidding just because they said so. ... There is no rhyme or reason or sense."
Malvo, who was 17 years old at the time of the shootings, said he was under the spell of Muhammad, who controlled what he ate, when he slept, what he read and his itinerary. The two had met in Antigua, where Malvo was bouncing between living with his mother and father and where he said he was subjected to abuse.
"He picked me because he knew he could mold me. He knew I could be what he needed me to be. ... He could not have chosen a better child," Malvo said. "He told me to do something, and I did it. After a certain point, he didn't have to say anything. He would just look at me, and I understood."
Malvo is serving a life sentence at Red Onion prison in Virginia for his role in the shootings. Muhammad was executed in 2009.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Exploding whale video goes viral on Internet