A 15-year-old boy testified today that murder suspect Wayne B. Williams picked him up in a car, drove him to a wooded area near a public housing project and fondled him through his trousers in August, 1980.

The testimony from the black youth, identified only as Darrell, was the first suggestion in court of a motive for 12 murders of young blacks prosecutors contend that Williams committed.

Darrell also testified that he saw Williams drive away from a shopping center with Lubie (Chuck) Geter, 14, on the weekend in early January, 1981, that Geter disappeared. Geter's body was found in a wooded area in southwest Fulton County about 15 miles from downtown Atlanta on Feb. 5, 1981.

Darrell also testified that he saw Williams leaving the funeral of Terry Pue, 15, whose body was found Jan. 23, 1981.

The Geter and Pue cases are among 10 that Fulton County Superior Court Judge Clarence Cooper is allowing prosecutors to introduce as evidence of a "plan, scheme, pattern, or bent of mind" in Williams' trial on charges of murdering Jimmy Ray Payne, 21, and Nathaniel Cater, 27.

Prosecutors say they have fiber evidence linking all 12 victims to Williams, plus bloodstains in Williams' car matching the blood types of two victims and several witnesses like Darrell who can place Williams with three victims.

Darrell said he was stealing newspapers from vending boxes and reselling them when a man in a white station wagon stopped and asked if he wanted a job.

When Darrell answered yes, he testified, the man, who said his name was "something like Jimmy," told him it would be a job washing cars, and drove him to a car wash, but found the car wash closed. Then the man asked about his brothers and sisters and whether Darrell played a musical instrument, the youth said, adding that he said he played drums.

Darrell testified that the man then asked if he had any money, and started feeling inside his pants pocket, fondling his genitals. Eventually, the man drove to a wooded area near the Carver Homes housing project and stopped, Darrell testified. The man then gave Darrell $2, the youth said. He asked Darrell if he had sex with boys, told him to unzip his pants, then got out of the car saying that he was going to the trunk, Darrell testified. At that point, Darrell said, "I jumped out and ran."

Darrell said he did not know the man's name then, or when he saw him with Geter or at Pue's funeral, but he later identified him as Williams.

"Is there any doubt in your mind?" Assistant District Attorney Jack Mallard asked.

"No doubt," Darrell said.

Under cross-examination by defense attorney Alvin Binder, Darrell sometimes seemed to become confused, but did not recant any testimony. He told Binder, "I can't forget his face . . . . I wake up from dreams at night and think about it. It makes me sick."

Darrell testified that he was cleaning debris from a shopping center loading dock on Jan. 3, 1981, when he saw Williams again, this time getting into a car with a boy he knew as Chuck Geter.

Darrell told the jury that although he did not know Pue he went to Pue's funeral because his counselor at a school for juvenile offenders was organizing pall bearers. Darrell said he pointed out Williams to Eric Thompson, 15, as "the man who grabbed me."

Thompson, who had known Pue, took the witness stand later to confirm Darrell's account.

Meanwhile, in a move that may indicate its future strategy, the Williams defense team is trying to subpoena participants in a June 19 meeting of high-level law enforcement officials that led to Williams' arrest two days later.

The defense has subpoenaed Georgia Gov. George Busbee, the director of the Georgia Bureau of Investigation and a former acting U.S. attorney in the Atlanta area. The defense also is trying to subpoena former Atlanta mayor Maynard Jackson, his press secretary and former Georgia attorney general Arthur K. Bolton.

During the seven-hour meeting at the governor's mansion in Atlanta the FBI briefed Busbee on the evidence it had accumulated against Williams and argued for his arrest.

The group included Fulton County District Attorney Lewis Slaton, the FBI agent in charge of the Atlanta office and members of Busbee's staff, but did not include Jackson or any other city officials.