An off-duty D.C. police officer was shot to death early yesterday in a gunfight with a 16-year-old boy who tried to rob him in Prince George's County, authorities said. The youth, who officials said had run away from a group home, also was killed.

Sgt. Clifton Rife II, 34, was flown by helicopter to Prince George's Hospital Center shortly after the 4:10 a.m. shooting in the 5400 block of Livingston Terrace in Oxon Hill. He was pronounced dead a short time later. Police said the youth, Jonathan M. Washington, was dead when officers arrived at the scene.

Authorities said Rife, a 13-year member of the D.C. force, went to the Riverview Terrace apartments and was walking toward a friend's apartment when Washington, wearing a mask and carrying a pistol, said he was robbing him. They said it was unclear whether Rife said anything in response. The two exchanged gunfire, with Rife using his service revolver. Rife was shot in the chest and the youth was hit several times in the upper body, authorities said.

"[Rife] managed to tell his friend that he had been shot, and help was called," said Officer Debbie Sabel, a police spokeswoman.

Washington, who lived with at least one relative at Riverview Terrace, had a juvenile arrest record, said police sources who spoke on the condition of anonymity because court records concerning minors are not public. The sources said Washington was charged this year with possession of heroin and was confined to a group home in the District. They said that he ran away from the home in January and that a warrant for his arrest was issued.

Relatives of Washington could not be located for comment yesterday.

Those who knew Rife remembered him as a hardworking officer who did not fear the streets. Assigned to the prostitution unit, Rife was "head and shoulders above any other candidate who applied" for the position, said police Cmdr. Hilton Burton, who had interviewed him for the job.

"He was just a dedicated guy who would do anything," said Burton, who now runs the 4th Police District.

In the hours before he was killed, Rife was serving subpoenas on his own time and was expected to return to work yesterday morning to attend a training session, said Capt. Mario Patrizio of the narcotics division, which oversees the prostitution unit.

"You got so used to him doing a great job that it just became the standard," Patrizio said.

Rife's productivity and seemingly boundless energy were noticed by police brass, said Assistant Chief Alfred J. Broadbent, who added that Rife "was outstanding. He was a cop's cop."

Rife, who joined the force in 1990 and was promoted to sergeant four years ago, had a wife and two young children, with whom he lived in Odenton.

Rife was the second D.C. police officer to die this week. On Sunday, Sgt. John S. Ashley, 37, collapsed and died after chasing a runaway dog in Northwest Washington. An autopsy is pending.

Outside the Riverview Terrace apartments yesterday, residents milled about the parking lot. Many said they were sorry that two people had lost their lives, and others described shootings and homicides and robberies, which they said occur frequently in the area. Last week, a pizza deliveryman was shot and seriously wounded. In March, a newborn boy was discovered dead in a plastic bag at Riverview Terrace.

One man stood behind the yellow crime-scene tape and watched as detectives scribbled notes and evidence technicians gathered items into large brown bags. He said that he heard about five shots but that he knew nothing else about the shootings.

"Seems every day there's something that brings [the media] here," said the man, who declined to identify himself because he feared becoming a target of violence. "It's to the point where you can't walk from your car to your apartment without thinking you'll get shot or robbed."

Staff researcher Bobbye Pratt contributed to this report.

Prince George's police work at the scene in the 5400 block of Livingston Terrace.

Passersby watch a police technician at the apartment complex in Oxon Hill where a D.C. officer and a 16-year-old boy shot each other. Sgt. Clifton Rife II, 34, who joined the D.C. force in 1990, lived in this townhome in Odenton with his wife and two young children.Angie Johnson, who lives in the Oxon Hill neighborhood, said she heard shots at the time of the gunfight that police say resulted in the deaths of Rife and Jonathan M. Washington.Rife "was outstanding. He was a cop's cop," one police official said.