A 16-year-old killed in a shootout with an off-duty D.C. police officer was probably involved in the abduction of at least one of two men discovered dead inside the trunk of a stolen car two months ago in Southeast Washington, investigators said yesterday.

The revelation only deepens the mystery surrounding what happened to Harvey L. Sumner, 58, and James L. Harris, 65, two men who apparently did not know each other but are linked by their deaths.

The men were found badly decomposed in the trunk of a stolen red Buick LeSabre on June 7. Investigators believe they had been in the trunk for about 10 days. Medical examiners have not determined the cause of death.

"We can't connect them until we find them in the car together," said Lt. David Jackson of the violent crimes unit. "Our investigation has included family members, co-workers, friends, any people we can find. But we just haven't found a link between the two men yet."

Yesterday, detectives released new details about their investigation. They also published security camera photographs on the department's Web site, www.mpdc.dc.gov, of a man and woman they would like to question.

The photographs were taken by a security camera about the same time Sumner's card was used in an ATM at a Bank of America branch in the 4600 block of South Capitol Street, police said.

Detectives have been unsuccessful in identifying the man and woman.

Meanwhile, they have been scrambling to determine what role 16-year-old Jonathan M. Washington played in the abductions and deaths.

Washington, who had a lengthy record of juvenile arrests and had run away from a D.C. group home in January, tried to rob a D.C. police sergeant at gunpoint as the officer walked toward a friend's apartment in Oxon Hill on June 2, police said.

The sergeant, Clifton Rife II, pulled out his police-issued weapon. They opened fire on each other and both died in the exchange of bullets.

Police said that they found Washington's fingerprint in Sumner's ransacked house in Temple Hills, pointing to his involvement in the abduction.

However, they do not believe Washington acted alone.

Sumner was last seen alive by neighbors on May 22 or 23, police have said. Investigators said they believe his house was badly ransacked sometime before 8 p.m. May 23.

About 10:50 p.m. May 23, someone tried to use Sumner's bank card at the Bank of America on South Capitol Street.

About four hours later, the card was inserted into an ATM at a Riggs Bank in the 4100 block of South Capitol Street, police said.

Two cars that Sumner used -- one that he owned and the other that he borrowed from the car dealership where he worked -- were also stolen from near his house in the 5500 block of Keppler Road in Temple Hills, according to investigators.

His Acura was recovered about noon May 25 in the 7000 block of Elkinds Avenue in Oxen Hill. The dealership's Hyundai Sonata was found seven hours later in the 8300 block of Indian Head Highway in Fort Washington.

That morning, the Buick in which the men were later discovered was reported stolen in Fort Washington, police said.

Police said they are even more confounded by what happened to Harris, a jazz enthusiast who lived in the 1800 block of U Street SE.

He was last seen alive by his ex-wife about 12:30 a.m. May 25, according to family members and police.

The family has said that his driver's license, library card and other items had been mailed to his apartment from the same Riggs bank where Sumner's ATM card was used. The envelope was postmarked May 24 -- a day before he was reported missing -- and he did not mention losing his wallet to relatives.

Police said the items were found outside the bank about 5 a.m. May 24.

Harris's 1984 BMW was stolen and recovered on Interstate 295 near Exit 1 on May 28, police said.

Anyone with information is urged to call D.C. police at 202-727-9099.

D.C. police say this woman and man used a slaying victim's ATM card.