RICHMOND, VA. ? A man sought as a material witness in the Washington-area sniper shootings was arrested Saturday, and prosecutors announced plans to charge the two suspects in Virginia, the second state where 17-year-old John Lee Malvo could face the death penalty.

Virginia prosecutors will charge the men Monday to cover two killings and one wounding there, said William Neely, Spotsylvania County, Va., commonwealth’s attorney.

Neely said he would seek the death penalty for John Allen Muhammad, 41. Malvo could face death, but Neely said his sentence would depend on his role in the shootings.

Virginia and Alabama where the pair are charged with killing a woman outside a liquor store in September allow the death penalty for crimes committed at age 17.

Earlier Saturday, a third man, believed to be the co-owner of a blue Chevrolet Caprice the suspects were found in a day earlier, was arrested and held as a material witness.

Nathaniel O. Osbourne, a man of Jamaican descent who has lived in Camden, N.J., was arrested at a home in Flint, Mich. He was to appear in court today but was not considered a suspect in the shootings, FBI Agent Barry Maddox said.

According to the New Jersey Department of Transportation, Muhammad and Osbourne bought the blue Caprice from Sure Shot Auto Sales Inc., Trenton, on Sept. 10.

Authorities say a hole cut in the car’s trunk could have allowed a sniper to fire at unsuspecting victims from the concealment of the car’s interior, leaving no evidence.

Federal agents escort Nathaniel O. Osbourne, second from right, to a waiting car in Flint, Mich. Osbourne, co-owner of the car used by the suspects in the Washington-area sniper shootings, was arrested without incident Saturday at a home in Flint. He is being detained as a material witness in the shootings.

Neely said Virginia prosecutors have been rushing to file charges to discourage federal authorities from filing charges.

“We’re having to go in in a hurry because we don’t want to be supplanted by the feds,” Neely said. “The ball is in their court. They have physical custody.”

Justice Department officials still were deciding whether to bring federal charges.

One official, speaking on condition of anonymity, said federal prosecutors could use the Hobbs Act, which allows the government to seek the death penalty in murders where killers try to extort money. Letters left behind demanded $10 million.

Authorities in Maryland were the first to file charges Friday, covering the six deaths in their area. They said they would seek the death penalty against Muhammad; Malvo would be tried as an adult, but the death penalty could not be applied there if his reported age of 17 is verified.

Montgomery County State’s Atty. Douglas Gansler said Saturday he hopes to continue discussions with other prosecutors about where the suspects will be tried first.