VIRGINIA BEACH, Va. - Describing John Allen Muhammad as a diabolical and mind- controlling killer, prosecutors told jurors yesterday that the sniper suspect turned a beat-up Chevrolet Caprice into a "war wagon" and a 17-year-old boy into an "instrument of death and destruction" to carry out the sniper attacks last fall.

The prosecution and the defense needed almost five hours to deliver their closing arguments yesterday, summing up a month of testimony and evidence that has closely tied the sniper shootings to Muhammad but has not put the murder weapon - a semiautomatic Bushmaster rifle - into his hands. Jurors will begin deliberations this morning.

Defense attorney Peter D. Greenspun sought to distance his client from Lee Boyd Malvo, the teen-ager from Jamaica whom Muhammad called his son and who has confessed to several of the shootings. Greenspun said that even if Malvo pulled the trigger in the attacks, there is no evidence that Muhammad ordered him to do so.

In order to impose the death penalty, jurors would have to conclude that Muhammad was an "immediate perpetrator" and "joint participant" in the killing of Dean H. Meyers at a Manassas, Va., gas station on Oct. 9 last year.

Alternatively, the jury of seven women and five men could find Muhammad not guilty, or guilty of first-degree murder, which carries a sentence of life without parole. Should they find him guilty, a sentencing phase would begin to determine his fate.

Lead prosecutor Paul B. Ebert said Muhammad's control over Malvo and his alterations that turned the Caprice into a "killing machine" make the 42- year-old Army veteran the "No. 1 perpetrator" of the shootings. Ebert noted the gunport in the car's trunk and the rear seat that hinged for easy access from the passenger compartment.

"Has anyone on this jury ever seen such an alteration - a seat you can lift up and a hole you can crawl into like some vermin so you can kill?" Ebert asked. "God knows, but for that man, [Malvo] would still be someplace else. He'd never have come to the D.C. area and have that weapon but for that man. He knows it and I know it."

Prosecutors suggested that Muhammad came to the Washington region to wreak havoc because his former wife had won custody of their children and taken them to Clinton, Md. Prosecutors believe extortion also was a motive because of the repeated demands made to police for money to stop the sniper killings.

Ebert noted Muhammad's courteous and polite nature, as described by many who came in contact with him. Ebert said that nature was evident in the notes and phone calls from the snipers to authorities last fall, which often ended with the words, "Thank you."

"This is the kind of man who would pat you on the back and cut your throat," Ebert said, adding that the courtesies allowed Muhammad to kill and get away with it so often. "They belie what's in his heart. They belie the evil within him."

Muhammad, as usual, showed little emotion yesterday. He occasionally cupped his hands in front of this mouth and blew into them, rubbing them together. He did not react when prosecutors showed photos of the sniper victims and played tapes of phone calls that threatened more killings if money was not delivered.

Muhammad's attorneys made little attempt to explain some of the most damning evidence, much of it found in Muhammad's car when he was arrested on Oct. 24, 2002. While Greenspun attempted to discredit some of the prosecution's witnesses in his two-hour closing argument, he mostly hammered on the lack of direct evidence.

In a manner almost resembling that of a law school professor, he carefully went over the judge's instructions to the jury and defined for them the meaning of the term "immediate perpetrator" as the person holding the gun - and no one else.

"The driver, the planner, is not the joint participant," Greenspun said. "The commonwealth has no evidence of direction or control or indoctrination by Mr. Muhammad over Mr. Malvo. So what they're trying to say is, he [Malvo] was obedient and so Mr. Muhammad made him do it. That's what their whole case comes down to."

Greenspun said only four of the 138 prosecution witnesses testified to the relationship between Muhammad and Malvo. He said the four said Malvo was obedient but did not speak of the kind of indoctrination suggested by prosecutors. That Muhammad is older and bigger than Malvo doesn't prove a thing, Greenspun said.

"They had a caring relationship," he said. "Sometimes they would read and discuss things together - that's it for their relationship. ... There's no evidence about what went on between Mr. Muhammad and Mr. Malvo."

The principal closing argument for the prosecution was delivered by Assistant Commonwealth's Attorney Richard A. Conway, who walked jurors through 15 shooting scenes and methodically tied each one to Muhammad and Malvo. Admitting the lack of direct evidence, he sought to make it clear that a sniper cannot operate alone.

"When you have a sniper-spotter killing team in a mobile urban hide, taking out innocent people as they go about their daily lives in order to create terror and intimidation, so that they can extort money from the government, [they are] nothing short of immediate perpetrators," Conway said. "Both of them, principals in the first degree."

During much of his two-hour closing, Conway appealed to the grief and emotion that have been brought out in harrowing testimony through the course of the trial. Prosecution witnesses included relatives of the victims, those who were with them in their final moments, and survivors of the attacks.