Two men alleged to be accomplices in the shooting of three undercover D.C. police officers last week surrendered at police headquarters yesterday, ending a six-day police search.

Thomas Fields, 18, of 1612 Thomas Rd., Fort Washington, and William Lee Lumpkin, 21, of 3013 14th St. SE, turned themselves in to homicide detectives shortly before noon, police said. The two men were accompanied by attorney G. Alan Palmer, who arranged for their surrender.

The men were charged with assault with intent to rob while armed, police said. "Both were anxious to get the surrender over with," Palmer said. "They knew they were in a dangerous situation and didn't want to remain fugitives."

Fields and Lumpkin, along with 20-year-old Herbert Austin, who was apprehended near the shooting scene and later was charged with assault with intent to kill, allegedly robbed and shot three undercover police officers last Wednesday at an abandoned gasoline station at South Capitol Street and Martin Luther King Jr. Avenue SW.

The officers had arranged to purchase PCP as a part of a drug investigation, police said. Two officers were shot as they stepped from their car, and a third officer was shot as he ran to assist the wounded officers.

Officer Troy Pumphrey, who received several gunshot wounds, was in stable condition at Hadley Hospital yesterday, hospital officials said. Officer Richard Watkins was shot in the leg, and Officer Gerald Awkard, who was wearing a bulletproof vest, was treated for a bruised back.

Police had obtained arrest warrants for Fields and Lumpkin and had been watching their homes. Palmer said family members called him last night, asking for advice.

"I said that the two men were in a very volatile situation because so many police were looking for them, and that the best thing to do was to give up," Palmer said.

The shooting of three officers was the third undercover police drug purchase in the past month that has resulted in officers being shot. Six D.C. officers have been wounded in the incidents.