The jury in the trial of John Allen Muhammad (search) failed to reach a verdict Friday after deliberating for four hours on whether Muhammad was the man behind the sniper spree that terrorized the Washington area last fall.

Circuit Judge LeRoy F. Millette Jr. (search) sent the jurors home at 1 p.m., the normal time the judge has adjourned court on Fridays. Deliberations will resume Monday.

The panel of seven women and five men began deliberations at 9:05 a.m.

"The case is now in your hands," Circuit Judge LeRoy F. Millette told the jury.

The jury came back at noon with a request for a tape recorder, which would allow jurors to listen to 911 tapes and calls purportedly made by the sniper suspects to enter negotiations with police.

Millette granted the request, despite defense lawyers' concerns that it might lead the jury to focus disproportionate attention on the tapes.

"Anything in evidence they should have the opportunity to review," Millette said. There wasn't a recorder immediately handy, however, and court officials were attempting to obtain one.

With no direct evidence that Muhammad ever fired a shot in last fall's sniper spree, jurors faced one crucial question: Was he the mastermind who holds ultimate responsibility?

Prosecutor Richard Conway said during closing arguments Thursday that Muhammad and Lee Boyd Malvo (search) formed "a sniper-spotter killing team" with Muhammad as the "captain." The defense argued that jurors have been "pounded" with emotional testimony that clouds the facts.

Muhammad, 42, is accused of killing Dean Harold Meyers (search) on Oct. 9, 2002 at a Manassas gas station. Like Malvo, he is charged with two counts of capital murder, one accusing them of taking part in multiple murders, the other alleging the killings were designed to terrorize the population.

If Muhammad is convicted, the trial will move to a sentencing phase to determine whether he will receive the death penalty. The sentencing hearing could take up to five days, prosecution and defense lawyers said.

Throughout the trial, prosecutors portrayed Muhammad as a father figure to the younger Malvo, a stern and controlling man who trained the teenager to do his bidding.

They presented no direct evidence that Muhammad fired the Bushmaster rifle (search) used in the crime, but say it doesn't matter. Malvo was so deeply under Muhammad's sway, they argued, that both share guilt.

"That is a young man he molded and made an instrument of death and destruction," lead prosecutor Paul Ebert said in closing arguments.

Malvo, now 18, is on trial just 15 miles away in Chesapeake for the Oct. 14 shooting of Linda Franklin at a Home Depot in Falls Church. He also faces a possible death sentence if convicted.

In his opening statement Thursday, Malvo lawyer Craig Cooley said Muhammad turned Malvo into a "child soldier," brainwashing him into thinking the killings were "designed to achieve a greater good of a fairer and righteous society."

Malvo's attorneys argue that Malvo was insane at the time of the shooting because he was indoctrinated by Muhammad. Cooley said Muhammad was seeking revenge against his ex-wife, Mildred, who had custody of their three children. He suggested Mildred Muhammad was to have been one of the shooting victims and that her death would have allowed Muhammad to carry out his plan.

"Had Mildred been No. 14 or No. 15 or No. 16, they wouldn't be looking for anybody else who had a grudge against her," Cooley said.

Cooley said that once Muhammad regained custody of his children, he would have taken them and Malvo to Canada and formed a Utopia. Before they could do that, though, they needed to take action to "make America wake up," Cooley said.

Fairfax County Commonwealth's Attorney Robert Horan said he planned to start his case with the Franklin and Meyers shootings when Malvo's trial, off Friday, reconvenes Monday.

The two slayings were part of a string of shootings that killed 10 people over a three-week period in October 2002 in the Washington metropolitan area. Prosecutors said the spree was an attempt to extort $10 million from the government.

Jurors in Muhammad's case have to decide if he is a "principal in the first degree" to convict him under a multiple-murder charge.

Muhammad, who began the trial as his own lawyer before handing the case back to his attorneys, sat stoically at the defense table as prosecutors wrapped up their case.

Jabbing a finger at Muhammad, Ebert said Muhammad came off as a polite man, but that his calm demeanor masked a calculating and sinister side.

"He's the kind of man who could pat you on the back and cut your throat. That is the kind of man who can kill time and time again," Ebert said.

But in closing arguments, Muhammad attorney Peter Greenspun said prosecutors had "pounded" jurors with gory photos and emotional witness testimony during the trial to convince them to make an emotional decision.

He urged the jury to look at the evidence, which he said doesn't prove Muhammad directed the shootings or fired the gun in the Meyers murder. Greenspun tried to cast doubt on several witnesses, questioning their credibility.

Greenspun also said prosecutors have not made a strong case that Muhammad had enough control over Malvo that the teen would kill on his orders.

An expert federal witness in Muhammad's trial also came under scrutiny Thursday. FBI and Justice Department documents obtained by The Associated Press showed a government chemist who testified for the prosecution has made numerous racial remarks and has an office so sloppy it has raised concerns of contaminated evidence.

The documents detail testimony from colleagues and supervisors that Edward Bender made racist comments that led at least one colleague to worry about his impartiality in cases. The prosecutor said he wasn't told by the government of the information, and defense lawyers declined comment.