A former Ballou High School student was arrested yesterday in connection with the slaying of Theodore "Teddy" Garvin, a star tennis player at the school who was shot last Friday as he sat on a Metrobus.

John Antwan Harris, 19, was arrested by Prince George's County and D.C. police without incident at 7:15 a.m. at his mother's home in the 4000 block of Buck Creek Road in Temple Hills. Harris, held on a charge of first-degree murder, will be arraigned this morning at D.C. Superior Court.

After his arrest, Harris was taken to the Prince George's police headquarters in Palmer Park, where he waived extradition rights and was transferred to the 7th District police headquarters in Southeast Washington.

The suspect was escorted by two plainclothes District officers when he arrived at 12:45 p.m., wearing a dark-colored sweat suit, his face partially hidden by a hood. He was scheduled to be interviewed by detectives before being moved to the department's central cellblock at 300 Indiana Ave. NW. If convicted, Harris could get 35 years to life in prison.

Garvin and Harris knew one another from Ballou, but police said they have no motive for the shooting.

"As far as we know, there was no bad blood between the two," Detective Bruce Faison, one of two lead detectives on the case, said during a news conference yesterday to announce the arrest. "It's a tragedy on both sides."

A young woman who answered the phone at the house of Garvin's grandmother yesterday said the family had no comment.

Garvin, 17, was shot once in the armpit as he sat down near a window on the bus along Wheeler Road in Southeast. Police allege Harris walked up to the bus, leaned into the window and shot Garvin. Garvin, a star tennis player and a member of the Ballou marching band, was on his way to visit his girlfriend and their infant son. No one was sitting next to him on the bus, police said yesterday.

Passengers on the bus heard a loud noise but didn't realize Garvin had been shot until about 10 minutes later when someone saw him slumped over. He was taken to D.C. General Hospital, where he died.

The handgun used in the slaying has not been recovered, Robinson said.

Police sources familiar with the investigation said someone identified Harris through police photos. Harris has had at least one run-in with D.C. police but has never been arrested for a violent crime in the District, according to 7th District Cmdr. Winston Robinson.

Harris's mother, Veronica McCarthur, was visibly shaken when police showed up at her house, detectives said.

"She was quite upset," said 7th District Detective Jamell Mayhew. "She didn't know what her son was into. She was speechless."

No one answered the door yesterday at McCarthur's modest red-brick rambler.

The shooting has puzzled police, who initially labeled the slaying random because there was no evidence that Garvin was involved with anything usually associated with that type of crime, such as drugs, gangs or other criminal activity, Robinson said. Police described him as "a clean-cut kid."

"We couldn't offer any explanation of who in the heck could kill this child," Robinson said, although police now believe Garvin was the intended target. He was involved in a recent altercation involving his younger brother and an unidentified male student at Ballou, but Robinson said yesterday that the fight "had nothing to do" with the slaying.

School district officials said Harris last attended Ballou during the 1998-99 school year. Garvin's brother Samuel is a junior at the school.

"It's an odd story," said a police source familiar with the matter.

Staff writers Emily Wax, Craig Whitlock and Debbi Wilgoren contributed to this report.