ROCKVILLE, Maryland (AP) — Prosecuters in the state of Maryland filed the first murder charges in the 13 sniper attacks that terrorised the Washington area, and authorities yesterday tracked down the co-owner of a blue Chevrolet Caprice in which the two suspects were arrested.

The man arrested yesterday was believed to have helped the two suspects buy the car, which was registered in New Jersey. Authorities say a hole had been bored in the trunk from which the snipers may have fired on their unsuspecting victims.

Ten people were killed in the attacks and three were wounded during the three-week rampage.

Federal Bureau of Investigation (FBI) spokeswoman Linda Vizi said Nathanel O Osbourne was arrested without incident yesterday at home in Flint, Michigan.

Osbourne, of Jamaican descent and described as a friend of Muhammad, was being held as a material witness and is not considered a suspect in the shootings, FBI Agent Barry Maddox said. He said Osbourne would likely be held during the weekend in Michigan until he appears before a federal magistrate.

In the Washington suburbs and into northern Virginia where the attacks had occurred, residents were returning to their shopping and everyday tasks yesterday with a sense of relief, while others mourned the death of the snipers’ final victim, a bus driver gunned down Tuesday.

“I don’t have to worry about walking outside and getting shot,” said Ryan Burditt, a student at Benjamin Tasker Middle School in Bowie, Maryland, where a 13-year-old boy became one of only three of the sniper’s 13 victims to survive.

On Thursday, John Allen Muhammad, 41, and teenager Lee Boyd Malvo, were arrested at a rest stop near Fredricksburg, Maryland. Authorities also wanted to talk to Osbourne and described him as a material witness.

Maryland authorities filed six first-degree murder counts Friday against Muhammad and Malvo covering the 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 if his reported age of 17 is verified. Maryland law does not allow for the death penalty against people under age 18.

As the first charges in the case were announced, federal and state officials began wrangling over whose case would take precedence — and new details emerged about the investigation of the shooting spree.

Justice Department officials are still deciding whether to bring their own 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. Law enforcement sources have said two letters left behind in the sniper cases demanded $10 million.

Early Friday, Alabama law enforcement officials filed murder charges against the two suspects in a September 21 liquor store robbery and fatal shooting in Montgomery and said they would seek the death penalty. The police chief, John Wilson, said investigators believe Muhammad fired the shots.