"We still don't know the whole story," Marshall said. "I'm not even going to speculate on what happened. We're waiting for the authorities to tell us."
According to a statement from the Hagerstown Police Department, Artis was found dead May 20 at about 7:20 a.m. in a parking lot at the rear of 60 East Ave., more than a mile from his home on Magnolia Court.
Artis had been shot once in the upper left arm hours before police found him. Police said the shooting occurred near Franklin and Locust streets.
Williams was charged Wednesday in Baltimore with violation of probation. Upon learning of the arrest, Hagerstown investigators asked that Williams be detained. On Friday city police picked up Williams from the Baltimore City Jail and brought him to Hagerstown.
Friday, Williams was charged with first- and second-degree murder, first- and second-degree assault, reckless endangerment, using a handgun in the commission of a felony and carrying a handgun, according to police and the Washington County District Court Commissioner's Office.
Friday night Williams was being held without bond at the Washington County Detention Center, according to the commissioner's office.
Hagerstown Police Department Sgt. Ronald Graves said it was unknown whether the suspect and victim knew each other.
Graves would not comment on a possible motive, what information led them to charge Williams or whether police had found the weapon used in the shooting.
"Field interviews played an important part in locating possible witnesses to this shooting," according to a police department statement.
During a previous interview, Marshall described Artis as a good kid who had made mistakes in the past.
He said Artis had some trouble adjusting to a new town and new friends when the family moved here almost four years ago.
Marshall said that Artis had turned a corner in his life, although he still did not approve of where Artis and his friends would go to hang out.
He said Artis had been working for about a month at a temporary employment agency and was considering joining the U.S. Marines.
Artis was preparing to graduate from North Hagerstown High School.