Defense lawyers contend that Malvo was brainwashed by sniper mastermind John Allen Muhammad, whom he considered his father, to a point where Malvo was legally insane and unable to tell right from wrong.
Malvo, 18, and Muhammad, 42, are accused of carrying out a three-week sniper spree that killed 10 people in the Washington D.C. area last year. Malvo is on trial for one of the killings — that of FBI analyst Linda Franklin. In a separate trial last month, Muhammad was convicted of another of the killings and a jury recommended a death sentence.
Prosecutors plan to let jurors hear from survivors of shootings linked to Malvo as they present witnesses this week to support their argument that the teenager told police the truth and lied to the psychiatrists.
"In virtually every way, Malvo's attorneys presented a much more complete defense than we saw in the trial of John Muhammad," said CBSNews.com Legal Analyst Andrew Cohen. "They focused upon Malvo's background, on his youth, on his relationship with Muhammad and on his mental state at the time of the shootings and I think in doing so gave jurors who are inclined to be sympathetic something to hold onto."
Although police said he confessed to the shootings after his capture, Malvo changed his story months later in interviews with defense mental health experts, saying Muhammad was the shooter in all but one of the 10 killings.
"We're trying to prove the defendant is lying to them," prosecutor Raymond Morrogh told the judge Thursday before court adjourned for a long weekend.
Defense mental health experts testified last week that Muhammad spent months indoctrinating Malvo by controlling Malvo's diet and exercise, telling him blacks were oppressed by the white government, teaching him to fire weapons, exposing him to violent movies and video games and isolating him from family and friends.
The last defense witness, psychiatrist Neil Blumberg, said the indoctrination left Malvo legally insane at the time of the killings. He said Malvo, who was 17 at the time of the sniper spree, confessed to the shootings because he wanted to protect Muhammad.
Prosecutors plan to begin rebuttal testimony by presenting their own mental health experts, as well as evidence about the other shootings.
Ultimately, "it's not so much a matter of whether the kid lied," said Radford University criminal justice professor Tod Burke. "It really comes down to whose experts you believe the most."
Defense attorney Craig Cooley objected to the additional prosecution testimony, saying rebuttal witnesses are supposed to counter what the defense witnesses told jurors, not what Malvo told the witnesses.
Circuit Judge Jane Marum Roush ruled against Cooley, saying that if Malvo is "an unreliable informant about his history ... isn't that something the jury should consider in determining whether the expert's opinion is credible?"