A beat-up former police car with 156,000 miles on it occupied the spotlight at convicted sniper John Allen Muhammad's second trial, as prosecutors sought to show how the vehicle was modified into a mobile sniper's nest.

Jurors in the trial saw the car up close on a brief field trip Wednesday from the courtroom to a courthouse loading dock.

The car is key to prosecutors' case against Muhammad, who is again on trial for the October 2002 killing spree that left 10 people dead in the national capital region. Muhammad has already been convicted and sentenced to death in Virginia for his role in the October 2002 sniper spree. His current trial is for the six killings in Montgomery County, Md.

Lee Boyd Malvo is serving a life term for another Virginia sniper killing and is charged with the same six Maryland murders but likely will plead guilty and testify against Muhammad.

The car had a hole bored in the trunk, allegedly for a rifle barrel, and the back seat was unhinged to allow access to the trunk and provide a hidden storage space for a Bushmaster rifle.

Investigators tore apart much of the Caprice's interior in their search for evidence. The car jurors saw had much of its flooring and door panels ripped off. The hub cabs had been removed. The back seat, which prosecutors said could be folded down so someone could lie in the trunk and fire the gun through the hole, was dislodged.

The car, which Muhammad bought for $250, yielded a wealth of other evidence. Inside it investigators found two-way radios, a scrap of paper with the sniper task force tip line phone number, and a paper with a list of schools in the Baltimore area, among dozens of items.

Also Wednesday, Muhammad, who is acting as his own lawyer, tried to question a witness about other sniper sprees in Ohio and West Virginia in an apparent attempt to suggest to jurors that he is innocent and the true sniper moved on to more shootings.

In late 2003 and early 2004, a sniper in the Columbus, Ohio, area killed one person in a series of random highway shootings. Charles McCoy Jr., arrested in March 2004, was sentenced to 27 years in prison after pleading guilty.

Muhammad's questions to Allan Stratos, an agent with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, about the sniper shootings in Ohio and West Virginia were cut off by the judge after prosecutors objected.

Prosecutors pointed out that none of the shootings in those states was linked to Muhammad's Bushmaster rifle, which was found in his car when he was arrested on Oct. 24, 2002.