John Allen Muhammad, who committed a series of sniper murders in Washington D.C. area in 2002, was convicted Tuesday of six more killings in Maryland, CBS News reported on Tuesday.

Muhammad, 45, is already under a death sentence in Virginia for a killing there. The most he can get for Maryland killings is life in prison without parole, according to the report.

A jury in Rockville, Maryland, took slightly more than four hours to convict him after a four-week trial in which he acted as his own attorney.

The three-week sniper shooting spree in the autumn of 2002 left ten people killed, and three wounded, in Virginia, Maryland and Washington D.C., as the whole capital area was gripped with great fear.

The trial marked the first time that Boyd Malvo, the young complice in the crime, testified against Muhammad, his former mentor and manipulator.

During two days of testimony last week, Malvo, 21, gave the first inside account of the shootings and described Muhammad's elaborate plans for a reign of terror.

Malvo, who originally claimed to have fired every shot in the crime, told the court recently that he pulled the trigger in three of the attacks, killing one man and injuring two other people, and the triggerman for the rest of the victims was Muhammad.

According to him, Muhammad planned two phases of attacks -- six shootings a day for a month, followed by a wave of bombings of school buses and children's hospitals.

Malvo said Muhammad also hoped to extort as much as 10 million U.S. dollars from authorities and use the money to set up a school in Canada to teach homeless children how to use guns and explosives.

After the trial, Muhammad could still face prosecution for earlier shootings in Alabama and Louisiana.

Source: Xinhua