Updated

John Allen Muhammad's conviction for six more murders in the Washington, D.C.-area sniper spree gives prosecutors the insurance they sought — that there is little chance he will leave prison alive.

Muhammad, 45, was convicted Tuesday after a monthlong trial in which he acted as his own attorney. The verdict adds to the death sentence Muhammad previously received for a sniper shooting in Manassas, Va. He faces a likely term of life in prison without parole when he is sentenced Thursday.

The trial also gave family members an explanation, however twisted, for the 2002 rampage in which Muhammad and his one-time protege, Lee Boyd Malvo, took aim at random people. Malvo, testifying for the first time against Muhammad, told jurors that Muhammad's original plan included far more bloodshed — and plans to bomb children.

"We may never know the whole truth, but we do know without a doubt, 100 percent, that Lee Boyd Malvo and John Allen Muhammad are the ones who committed the murders," said Vicki Snider, whose brother, James L. "Sonny" Buchanan, was killed while mowing grass near a suburban mall.

The jury took about 4 1/2 hours to reach a verdict about the murders of James Martin, Premkumar Walekar, James "Sonny" Buchanan, Sarah Ramos, Lori Lewis Rivera and Conrad Johnson. In all, 10 people died and three were wounded during the three-week spree.

Muhammad stood grimfaced with his arms folded across chest as it was read. As he was led from the courtroom he said, "Your honor, may I speak?"

"No sir," Montgomery County Circuit Judge James Ryan answered.

The Maryland trial featured a dramatic showdown between Muhammad and Malvo, who said Muhammad treated him like a son but molded him into a killer.

Malvo's testimony came after he agreed to plead guilty in the Maryland killings. He was not promised leniency, but told jurors he wanted to face the man who he said trained him to be a killer. Malvo called Muhammad a "coward" and, at one point, glared at him, saying: "You took me into your house and you made me a monster."

He gave detailed descriptions of each shooting, even pointing out parking spaces where the sniper team's car was parked.

The 21-year-old also testified that Muhammad had plans for even greater carnage than the 10 killings and three woundings that occurred over a three-week span. Muhammad planned a first wave of violence to include six shootings a day for 30 days, Malvo said. In Phase Two, school buses and children's hospitals would be bombed.

Jurors found Malvo credible, said juror Scott Stearns, the White House correspondent for Voice of America. But it wasn't absolutely necessary for a guilty verdict, he said.

"It was certainly compelling testimony from a troubled young man," said Stearns, of Kensington. "As much as Malvo was responsible for those killings, I think it took courage for him to take the stand and confront his mentor."

One of the attorneys who helped Muhammad with his defense said Muhammad was disappointed but not surprised by the verdict. Muhammad felt he did not get a fair trial because he was blocked from presenting evidence that he thought would prove he was set up.

"When you give the jury only one side of the story, you can't expect them to do anything other than what they have done," said attorney Jai Bonner.

Aside from Malvo's testimony, Muhammad's second trial followed the blueprint established by his first, with prosecutors telling jurors that Muhammad and Malvo roamed the area in a beat-up Chevrolet Caprice, firing .223-caliber bullets from inside its trunk at people at gas stations, parking lots and a school.

Jurors heard a torrent of evidence that linked Muhammad to the shootings, including the rigged car with a hole bored in the trunk for a rifle barrel. Prosecutors presented ballistics evidence that tied the bullets used in the shootings to the Bushmaster rifle found in the car when Muhammad and Malvo were arrested.

Muhammad claimed he and Malvo were simply searching the Washington region for his children, who had been taken away from him in a custody battle with his ex-wife. He implied that authorities framed him, planting items such as DNA and gun evidence to convict him.

He struggled to mount a defense, hampered by his failure to meet deadlines on calling witnesses. He originally wanted to call hundreds of people to the stand, but the judge limited him to just a few dozen because he failed to follow proper courtroom procedure.

During closing arguments, Muhammad sometimes shouted as he quoted the Bible, Mark Twain and Groucho Marx.

Following his sentencing Thursday, Muhammad is scheduled to return to Virginia. He still faces possible prosecution for earlier shootings in Alabama and Louisiana, and he and Malvo are linked to other shootings in Maryland, Arizona, Georgia and Washington state.