Leslie Malvo testified for less than 15 minutes and over the objections of prosecutors, who unsuccessfully sought to bar Leslie Malvo's testimony in its entirety.
Jurors also heard Monday from a Jamaican investigator who retraced Malvo's life and a Bellingham, Wash., mission director, reports CBS News Correspondent Barry Bagnato. There was no prosecution rebuttal.
Leslie Malvo lived with his son in Jamaica until Lee Malvo turned 5, at which point the mother, Una James, moved away and took Lee with her. The father and son saw each other only a few times after that.
From the age of 3, Lee Malvo wanted to be a pilot, Leslie Malvo said.
"The two of us would watch the planes coming down," he said. "Lee loved it very much."
Prosecutor Robert F. Horan Jr. said Leslie Malvo's testimony should not be allowed because he testified in the guilt phase of the trial and had little to offer.
"He sat on the witness stand and sobbed and cried for 20 minutes about the precious son he hadn't seen in 10 years," Horan said. "The jury should not be subjected to that testimony."
A social worker testified Monday that Malvo changed his behavior and attitude while in jail, slowly breaking away from Muhammad after hearing from people from his childhood in Jamaica.
Carmeta Albarus, herself a Jamaican native, said Malvo initially had been uncooperative after his arrest but slowly came around after having phone conversations or listening to audiotapes from his father and from a teacher with whom he had a special bond in Jamaica.
"The turning point was hearing his father's voice," she said, which elicited tears from Malvo.
The defense presented testimony it hopes will convince the jury to spare Malvo's life. He was convicted last week of capital murder for his role in last year's sniper spree in and around Washington, D.C.
The defense testimony in the sentencing phase was brief because much of the testimony was heard during the trial's guilt phase, when Malvo had presented an insanity defense.
Malvo was found guilty Thursday of killing FBI analyst Linda Franklin on Oct. 14, 2002, during the three-week shooting spree that left 10 people dead and three wounded.
Jurors now must decide whether Malvo should get the death penalty or life in prison without parole.
During the guilt phase, Malvo's lawyers mounted an insanity defense, claiming indoctrination by John Allen Muhammad had left Malvo incapable of telling right from wrong.
A jury in Virginia Beach last month recommended the death penalty for Muhammad, 42, after convicting him of capital murder.
Malvo's trial had been mostly devoid of emotional moments until the sentencing phase began. But the testimony grew intense and jurors wept as relatives of some of the victims testified about their loss.
Franklin's daughter, Katrina Hannum, said her mother was the "golden thread" that held her family together.
"I lost my whole family the day I lost my mother," Hannum said.
Myrtha Cinada, whose father, Pascal Charlot, was killed, avoided looking at Malvo until the end of her testimony.
Then, she turned toward him and said, "I would like to say, Malvo, you are evil. You're insane because you took my father's life. Because of you, he didn't have a chance to see his great-grandchild. That's insane of you to do. You're evil."
Defense witnesses talked about a very different side of Malvo.
Esmie McLeod, vice principal at a high school once attended by Malvo in Jamaica, said the boy she considered a friend was warm and friendly but also sad and lonely at times.
"He was very witty," McLeod said. "There was a refreshing spontaneity to Lee Malvo. I thought he was such a sweet child that he would be any parent's pride and joy."
McLeod wept as she recalled Malvo's constant uprooting by his mother and said that he had had "brilliant prospects as a student."
Winsom Maxwell, a teacher in Jamaica who briefly took Malvo into her home when he was 11, described him as "a sad boy searching for love."