John Lee Malvo's lawyers said they would seek to bar his confession to being the triggerman in several of the Beltway Sniper shootings, including the Oct. 14 slaying of FBI analyst Linda Franklin.

Malvo talked to investigators for seven hours after he and his alleged accomplice, 41-year-old John Muhammad, were handed over to Virginia authorities Thursday for prosecution on death-penalty murder charges.

Malvo's lawyer, Michael Arif, criticized police for questioning 17-year-old Malvo without his court-appointed guardian or attorney and for leaking the alleged confession.

Sources told The Washington Post that Malvo was talkative and even bragged in some of his responses, but kept quiet about Muhammad.

Fairfax County prosecutors charged Malvo with capital murder in Franklin's killing.

Arif said the leak "suggests an insecurity on the part of the commonwealth with the admissibility of these statements."

For a murder conviction, prosecutors must show that the defendant was the triggerman. However, under the state's post-Sept. 11 anti-terrorism law, Muhammad could face the death penalty even if he is not found to be the gunman.

A Fairfax County police spokesman declined to comment on the interrogation, and Fairfax County Commonwealth's Attorney Robert F. Horan Jr. did not return calls.

Muhammad is being prosecuted in Prince William County for the Oct. 9 slaying of Dean Harold Meyers. It is unclear how Malvo's alleged confession to that crime might affect Muhammad's case.

Muhammad's attorney, Peter Greenspun, declined to comment on the case directly, but said the interrogation of Malvo without his court-appointed representatives was wrong.

"I think everybody should be concerned about that, not just lawyers," he said.

Todd G. Petit, Malvo's appointed guardian, said he went to police headquarters Thursday and asked that questioning be halted. Petit said a police commander agreed to pass on his request, then ordered him to leave.

Arif said he will seek to suppress any incriminating statements.

Meanwhile, Nathaniel O. Osbourne, the New Jersey man who befriended the two suspects, said he felt sorry for them and helped Muhammad buy and register the blue 1990 Chevrolet Caprice that was later allegedly used in the attacks.

"He never talked to me about anything of a criminal nature," Osbourne told the Post in Monday's editions. "People may ask, 'Did they present themselves as vicious criminals?' And I never saw that."

Osbourne, who was freed last week by federal authorities after being detained as a material witness, said when they arrived in New Jersey in early September, apparently by bus, they were disheveled and nearly penniless, reeking in soiled clothes. Their goal, he said, was to get a car to continue their travels.

"They wanted a car from the beginning," Osbourne said.

"I had great compassion for them when I saw them," he recalled. "I looked at them, man, and said to myself, 'Life is no promise. There is no guarantee."'

The Associated Press contributed to this report.