The murder case began almost two years ago with a robbery of the Berkley Farms Market in northeast Washington. Three men were shot and hacked to death. A fourth, Benjamin Washington, was slashed repeatedly with a machete and doused with cleaning fluid, but somehow he survived.

After spending nine hours in surgery at D.C. General Hospital, Washington, then 31, was questioned twice by police in three days as he lay in the hospital's intensive care unit. Both times, Washington was unable to say whether he recognized any of the assailants.

On the fourth day, however, Benny Washington summoned police to his hospital room and told them that he now remembered one of the assailants. Washington said it was a man who had worked with him at the store, a man named Melvin Douglas Downing.

As it happened, D.C. police had already amassed circumstantial evidence that they thought linked Downing to the crime. Washington's identification, and more evidence gathered after Downing's arrest, gave police what Det. Robert L. Chaney Jr. thought of at the time as "every element . . . perfect case."

Eighteen months later, however, Melvin Downing walked out of D.C. Jail a free man. One D.C. Superior Court Jury convicted him of the Berkley Farms Market murders, but another jury had later cleared him of the same charges.

The prosecution of Melvin Downing had become a bizarre example of how legal strategy and differences in the way two juries evaluate essentially the same evidence can sway the outcome of a court case.

In July 1976, Downing, then 23, was convicted of the murders at the Berkley Farms Market by a Superior Court jury of six men and six women. He was granted a new trial, however, after it was disclosed that one juror the lone holdout for acquittal - had changed his vote after telling his fellow jurors that he had visited the scene of the crime. The juror later told the court that he had concocted that story to ease tensions in the jury room and to "save face," apparently because he was embarrassed that he had delayed the verdict and changed his voice. Nevertheless, the judge, Sylvia Bacon, ordered a new trial.

Last month, a second Superior Court jury of eight women and four men acquitted Melvin Downing of all charges in connection with the slayings. As foreman Kimberly Johnson, 23, stood and announced the jury's decision to acquit Downing, Det. Chaney stormed out of the courtroom in anger and disbelief.

Benny Washington, who said recently that he still dreams about the horror he saw in the market that night, was sitting outside the courtroom when the second jury returned its verdict. "My brother went in . . . when he came back out . . . he told me 'Man, they found him not guilty of all counts,'" Washington recalled. "I couldn't believe it. I just couldn't believe it."

It was the government's theory that three men were involved in the Feb. 7, 1976 slayings at the market, located at the corner of Florida Ave. and Owen Street, NE. The prosecution contented that one of the men, Robert Trice, of 3419 22nd St. SE, acted as the lookout while Downing, armed with a pistol and a juvenile, armed with a machete, entered the market shortly after midnight.

Inside the store were the owner, Samuel J. Tillman Jr., 27, his cousin Benny Washington, another cousin, Raymond R. Washington, 27, and a customer, Charles Edward Scott, 32. According to Benny Washington, all four men were ordered to lie face down on the market floor.

When he heard the first shot, Washington said, he got up and ran for the rear of the store. He called for the other men to get up. Washington said in a recent interview, but "they just froze." Tillman, Scott and Raymond Washington were all shot in the head and Tillman and Scott's bodies were backed with a meat cleaver and a machete.

Benny Washington was slashed with the machete, splashed with cleaning fluid and seriously injured. "I know they thought I was going to die, but I don't know whey they quit," Washington said later.

Within 10 days, Downing, Trice and the youth were arrested and charged with homicide.

The government's evidence against Downing formed "a good case," said Judge Eugene N. Hamilton, who presided at Downing's second trial, "but . . . it was (also) a case about which in unusual circumstances a juror could have a resonable doubt."

Each of the two juries deliberated about four days and each examined pieces of physical evidence they took into jury room. Each time, according to jurors interviewed later, there were long and sometimes heated discussions about what they had seen and heard during the trial.

In the end, each verdict turned on the testimony of Benny Washington, the lone surviving witness, some clothes and some differences in the way the case was presented to each jury.

At each trial, Washington's identification of Downing was the key to the government's case. Both juries saw a flaw in Washington's testimony - his failure to give the police Downing's name during the first two interviews in the hospital. They also were concerned about how Washington's injuries may have affected his ability to remember accurately what happened.

Police investigators nevertheless felt they had developed an unusually strong case against Downing.

A bloody machete was found on the roof of Downing's sister's house. A pack of food stamps later was discovered under a mattress in her house.

On the stamps were fingerprints, identified as those of Downing and some of the dead men. Blood stained gloves were retried from a field nearby.

In a sewer near the home of Downing's girl friend, police, acting on tip, found a set of clothes, a machete sheath and a gun, later identified as one of the murder weapons. On the clothes, police analysts found strands of hair, similar to Downing's.

Later, Downing's defense attorney would argue that the physical evidence was insufficient to convict his client of murder.He suggested that the evidence was planted to implicate Downing in the crime. Downing's sister testified that her brother had given her the food stamps before the time of the slayings.

On the day after the murders, Downing's girl friend, Audrey Henson, then 14, allegedly told police in a sworn statement that Downing had told her about the murders and that the clothes were hidden in the sewer.

But, "the bottom line was Benny Washington," said assistant U.S. Attorney Martin J. Linsky, who prosecuted Downing at both trials.

"We took the position very strongly that (he) told truth," Linsky said in an interview.

The first jury apparently agreed.

"I thought he could identify the person who injured him," recalled a juror for the first trial. "He could be hazy . . . (but) I don't think he could be absolutely, totally wrong."

The second jury could not resolve its doubts about what Washington told them.

"For somebody to be an eyewitness to something . . . we had too many questions," remembered Kimberly Johnson, foreman of the second jury.

Johnson said the second jury also recalled testimony that during the third interview at the hospital, police had asked Washington if Downing "did this to you" and Washington responded that he had.

According to Johnson, the jurors felt "like (the police) were putting the idea in (Washington's) head."

The police deny that they mentioned Downing's name to Washington before he made the identification.

"Benny had known Melvin, so there shouldn't have been any problem," another juror said. "He should have pointed the finger at him right off the bat."

Between the first and second trials there were changes in strategy on both sides and various legal developments concerning crucial witnesses that also contributed to the differing verdicts, according to interviews with jurors.

A significant difference between the two trials involved the clothes - a pair of pants, shoes, gloves, two shirts, two pairs of socks and a cap - found in a sewer near the house of Downing's girl friend.

At the first trial, Linsky simply introduced the clothes into evidence, for the jury's inspection during its deliberations. It was the government's theory that the clothes had been worn by Downing during the market slayings.

At the second trial, however, Linsky decided to have Downing try on the fit. In a counter move, defense attorney R. Kenneth Mundy had the 15-year-old youth who the jury knew had already been found guilty in the Berkley Farms Market murders, try on the same clothes.

It was, Mundy said later, "a master stroke."

Jurors recalled that they thought Downing looked stuffy in the clothes. In a dramatic move during the second trial. Linsky pulled at one of the shirts while it was on the youth in an attempt to show the jury that it did not fit.

The youth's presence in the courtroom and his failure to testify, raised further questions in their minds, jurors said.

"We thought he was going to take the (witness) stand," one juror said. "It was one of the things we had hoped for."

Linsky explained later that the government was unable to call the youth to testify because he has appealed his juvenile court conviction and had a constitutional privilege against having to testify against his will in any trial related to the market slayings.

The jury also was aware that the third man, Robert Trice, had pleaded guilty to second degree murder in connection with the market slayings. Trice, however, did not testify at the second trial.

"We wondered why . . . that was something we kept talking about," a juror at the second trial said. The jury did not know that the government had prevented itself from calling Trice as a witness at the second trial. When Trice decided to plead guilty after Downing was convicted at the first trial, the government promised never to call Trice to testify against Downing.

Court prevented the government from explaining to the jury the absence of the two men because it could be prejudicial to Downing's case.

The jury was left to draw its own conclusions. "I felt that if . . . they knew anything . . . there was some way the prosecutor could get them on the stand to testify," one juror said.

Downing's failure to testify at the first trial hurt him with that jury. "If indeed you are not guilty, why can't you get up and speak for yourself?" recalled one of those jurors.

Mundy, Downing's lawyer said "at the first trial I didn't think it was necessary" to put Downng on the witness stand and subject him to Linsky's cross-examination. "I learned from the first experience."

At the second trial, Downing testified his own defense that he was at his sister's house and later at his girl friend's mother's house when the slaying took place. He told the jury that Benny Washington and the police were trying to set him up as a murderer.

"I was waiting to see if Linsky could shake (Downing's) testimony down some way, but the he couldn't," a juror on the second panel said.

When Downing's sister, Debra Denise Seals and his girl friend's mother also testified that they were with Downing the night the murders occurred, "everything fell right into place," the juror said.

Both juries also had to deal with the conflicting testimony of Audrey Henson, the girl friend who told police that Downing told her about the crime. According to court records, Henson now lives at 605 46th Pl. SE.

At the first trial, Henson testified that Downing told her about the crime but, under cross examination, she denied that Downing told her about the incident and claimed that police had harassed and threatened her into making the statement against Downing. When questioned again by Linsky, and when confronted by her earlier statement to the police, Henson said Downing had told her about the gun and the clothes in the sewer but not about any killings.

Henson refused to testify at the second trial. Since she had told, under oath, two different stories at the first trial, no matter what she told the jury at the second trial would subject her to possible perjury charges. So, through her lawyer, she successfully claimed her constitutional privilege against self-incrimination.

So Henson's testimony at the first trial was read to the second jury.

"The first jury thought Audrey was trying to help Melvin," said defense attorney Mundy. "She wasn't a real excellent witness."

At the second trial, when her original testimony was simply read to the jury, Mundy said, "the cold written word came across as neutral."

"What can you say? . . . She testified both ways," said a member of the second jury.

By the time the second trial ended, "there were just a lot of loose ends," said Wanda Ferebee, 19, a member of the second jury.

For example, several jurors questioned the government's theory that the killings stemmed from an armed robbery. An attache case containing $3,200 was left behind in the store office and later discovered by police.

According to the government, food stamps an undetermined amount of money were taken from a cash register, a cash drawer and an open safe.

"What was taken? Food stamps? Are you going to shoot three people in the head for food stamps?" one juror asked.

Futhermore, jurors said they were concerned that while the government theorized that two men entered the store that night, Benny Washington had said that he thought three men had come into the market.

"Of all the evidence," jury foreman Johnson said, "the only link they had to Melvin Downing was a strand of hair (on the clothes) and a fingerprint on a $10 food stamp."

The government "didn't prove (its case) beyond a reasonable doubt," said another member of the second jury. "Everybody on the jury said they could live better if Melvin was guilty and on the streets than innocent and in jail.

"Nobody was sure, everybody had doubts."