A Fairfax County judge, responding to complaints from lawyers for sniper suspect John Allen Muhammad, yesterday ordered that any Fairfax law enforcement officer or employee who provides information to the media about the investigation be subject to criminal prosecution for contempt of court.

In a further attempt to stop the unauthorized flow of information about last fall's sniper shootings, defense lawyer Peter D. Greenspun yesterday obtained subpoenas in Prince William County for five investigators and four Washington Post reporters to find out the sources for an article that appeared in The Post on April 6.

Citing law enforcement documents, the article reported that Muhammad's alleged co-conspirator, Lee Boyd Malvo, told investigators details of how the sniper shootings were arranged and carried out, and that Malvo acknowledged pulling the trigger in at least some of the killings.

Ten people were killed and three wounded in last October's shootings in the Washington area. Muhammad and Malvo were arrested Oct. 24 and charged with capital murder, accused of trying to extort $10 million from the government in exchange for a halt to the shootings. Muhammad, 42, is being tried in Prince William County for the Oct. 9 killing of Harold Dean Meyers at a gas station outside Manassas. Malvo, 18, faces trial in Fairfax for the Oct. 14 killing of Linda Franklin in the Seven Corners area.

After two weeks in federal custody, Malvo and Muhammad were taken to Virginia on Nov. 7 and then sent to different counties. Malvo met with Fairfax police Detective June Boyle and FBI Special Agent Brad Garrett that night, and he apparently spoke with them and other investigators for about seven hours. After The Post first reported parts of Malvo's statements on Nov. 10, Greenspun filed for an injunction against both Fairfax and federal investigators that would prohibit them from disclosing such information before trial.

Federal authorities were dismissed from the case, and Greenspun and Fairfax agreed to an injunction Dec. 11. It required that Fairfax police, among other things, not disclose the "existence or contents of any admissions, confessions or statements" of a suspect -- a police policy that is standard in all cases. There is no Virginia law prohibiting pretrial disclosure, but lawyers' professional rules set strict limits on the amount of information that can be released before trial.

But after the April 6 article disclosed more details of Malvo's statement -- citing law enforcement documents that summarized the interview -- Greenspun sought to have the Fairfax police department held in contempt of court. At a hearing yesterday, he asked Fairfax Circuit Court Judge David T. Stitt to hold an evidentiary hearing on what he called the latest "leaks," to appoint a special prosecutor to investigate, and to empanel a special grand jury to charge anyone found to be violating the Dec. 11 injunction.

"We've got a man's life in our hands at this point," Greenspun said of his client, Muhammad, who has not spoken to police. Malvo's lawyers have chosen not to pursue sanctions against those talking to the press, but Greenspun said the statements attributed to Malvo not only hurt Muhammad but poison the pool of potential jurors for both men's trials. "These jurors must not be subjected to this barrage of misinformation," Greenspun said.

Greenspun did not present evidence or call any witnesses to demonstrate who may have provided the documents or other information. Fairfax officials said in court that they were not the newspaper's sources.

Fairfax Commonwealth's Attorney Robert F. Horan Jr. said he, too, was disgusted by the release of information. He said an internal investigation was continuing to determine where the information came from, but he said he was confident it did not come from anyone in Fairfax. He suggested that Greenspun may have provided it, since the information wasn't about Muhammad, but Greenspun denied the accusation.

Stitt acknowledged that the information created problems for both sides. "My problem is," he said, "I don't have any evidence before me as to who is leaking the information and the documents." He declined to order a hearing, investigation or grand jury, but he agreed to enter an order threatening criminal prosecution for sources of information. The order applies only to Fairfax employees.

In Prince William, a hearing is scheduled for Thursday on the same subject. Greenspun asked the court to issue subpoenas to Boyle, Garrett and three other task force investigators to compel them to testify at the hearing. He also requested subpoenas for four Post reporters -- Sari Horwitz, Josh White, Maria Glod and Tom Jackman. The court issued the nine subpoenas yesterday.

Eric N. Lieberman, a lawyer for The Post, declined to comment.

Lawyer Peter Greenspun, with sniper suspect John Muhammad, said leaks are prejudicing potential jurors.