A man sought as a material witness in the Washington-area sniper shootings was arrested, 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 file charges tomorrow to cover two woundings and at least two of the three killings there, said William Neely, chief prosecutor of Spotsylvania county, Virginia. Neely said yesterday he will 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. The two also face six counts of murder each in Maryland, where prosecutors say they would seek the death penalty against Muhammad. Malvo, who is of Jamaican descent, would be tried as an adult, but the death penalty could not be applied there if his reported age of 17 is verified. Yesterday, 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, New Jersey, was arrested at a home in Flint, Michigan. He was to appear in court today but was not considered a suspect in the shootings that began October 2 and killed 10 people and critically wounded three.