A D.C. Superior Court jury yesterday acquitted a man charged with felony murder in a case in which another man resembling him spent nearly a year in jail.

Albert C. McCoy, 29, who is serving a five-to-30-year sentence for armed robbery at Lorton, also was acquitted of armed robbery, attempted robbery, armed kidnaping and carrying a pistol without a license. The charges stemmed from the November, 1975 slaying of Linda R. Black, 33.

Black was shot in the head, and a man was robbed and put in the trunk of a car by one of two men the victims had ridden around with in the city.

The government centered its case around the testimony of Richard E. (Ricky) Harris, who admitted his role in the incident and pleaded guilty to a lesser charge of robbery and received a two-to-six year sentence after making an agreement with the U.S. Attorney's office to testify against McCoy.

Harris testified that a man called "Shorty" was the triggerman in the case and pointed out McCoy in court Wednesday as that man. The government's case was weakened Tuesday when Harris said he was not exactly sure" the man in the defendant's seat was indeed "Shorty."

Earlier in the investigation, the man who had been put in the trunk and another witness identified through police photos and lineups William Sam Wylie, 33, of 324 61st St. NE, a friend of Harris' mother, according to court testimony.

Homicide detectives and the assistant U.S. Attorney trying the case, William J. Hardy, said they ultimately became convinced of Wylie's innocence.

Hardy said that, ironically, the government would have had a better chance of convicting Wylie.

"We could have got him," Hardy said, "but we're sure he's not the one who did it. At least in his case, justice was done."

Wylie testified that he spent 11 1/2 months in D.C. jail while awaiting trial on the charges before they were dropped in December, 1976. He was called to testify so jurors could see the striking physical resemblance between him and McCoy.

"It wasn't a surprising verdict based on the evidence," said Alan B. Soschin, McCoy's lawyer. "The government obviously had an uphill battle since two of his witnesses identified someone else."

The jury's forewoman said after the trial that there simply "wasn't enough evidence that he was guilty beyond a reasonable doubt."

D.C. homicide detective Jeff Greene said he was surprised that Harris changed his story and denied Soschins contention, made in his closing argument, that Harris was "threatened."

"There was absolutely no coercion at all," Greene said. "It's very difficult to walk into court and see the man face to face and then finger him on a felony murder rap."