John Wesley Griffin, the last Black Muslim to be prosecuted in connection with the massacre of seven Hanafi Muslims here in January, 1973, was acquitted yesterday of all charges by a D.C. Superior Court jury.

Although Griffin, 32, has now been cleared of any involvement in the slayings, he still must serve a life prison term for the murder of another defendant in the Hanafi case. That killing took place in a Philadelphia prison cell in 1974, and Griffin's conviction on that charge is being appealed.

Griffin and three other Black Muslims were convicted of the Hanafi murders by a Superior Court jury more than three years ago. Griffin was awarded a new trial, however, when a conflict arose in the testimony of the government's key witness, Anina Khaalis, one of two survivors of the massacre. Griffin was prosecuted a second time, but the case ended in a mistrial when Khaalis, for medical reasons, was unable to complete her testimony.

Griffin's third trial began Oct. 11. The jury of five men and seven women deliberated for three days before it delivered its verdict yesterday afternoon to Judge Leonard Braman.

"I'm happy for John, I've been deeply impressed by his faith and intelligence," said Dovey J. Roundtree, who defended Griffin along with attorney Veda Clark. Both women were appointed by Braman to represent Griffin.

U.S. Attorney Earl J. Silbert said in an interview that "the jury verdict . . . is a great disappointment." The government prosecutors, Lawrence Wechsler and Henry F. Schuelke III could not reached for comment.

The government contended that the Hanafi slayings arose from a religious dispute between the Black Muslims and Hamaas Abdul Khaalis, the leader of the Hanafis. Khaalis reportedly had angered Black Muslims by distributing letters critical of their leader, Elijah Muhammad.

At the time of the Hanafi murders, the Black Muslims were formally known as the Nation of Islam. During the past two years, however, the group has changed its name to the World Community Islam in the West.

The mass slaughter at the Hanafi house, at 7700 16th St. NW on Jan. 18, 1973, was in retaliation for those letters, the government contended. All the victims, five of whom were children, were members of Khaalis' family.

Those slayings led in part to the takeover last March by 12 Hanafi Muslims, including Khaalis, of three downtown Washington buildings. One person was killed and 149 others taken hostage during the sieges. At the time, Khaalis demanded among other things that the Black Muslims convicted of the murders be turned over to him for punishment.

All 12 Hanafi Muslims were convicted of various charges last August in connection with the takeover of the buildings and are now serving long prison terms.

Roundtree argued at the close of Griffin's third trial that the government had offered no tangible evidence that Griffin was in Washington on the day of the Hanafi slayings.

Roundtree contended that the government was trying to convict Griffin on the basis of a mass of circumstantial and physical evidence that may have implicated other Black Muslims in the crime, but not Griffin.

Roundtree questioned the reliability of Amina Khaalis' identification of Griffin as the man who took her 14-month-old daughter from her the day of the murders. The child was subsequently murdered.

Amina Khaalis made the identifiaction of Griffin during the first trial. But at the trial of another Hanafi defendant she identified a different man as the one who took her child, which resulted in Griffin's getting a second trial. Khaalis left the witness stand during the second trial and refused to return to court, so Braman declared a mistrial.

At the start of the third trial, on the basis of doctor's examinations of Khaalis, Braman determined that the woman was medically and legally unable to testify. So her prior testimony was read to the third jury.

The government's case against Griffin rested heavily on Khaalis's identification, but new evidence was introduced at the third trial that the prosecutors claimed linked Griffin to the crime.

One witness testified that she heard Griffin talk of retaliation against Hamaas Khaalis for letters. Another witness, Griffin's first wife, said he made statements to her that indicated he had knowledge about weapons used in the Hanafi slayings.

In addition to Griffin, six Black Muslims, all from Philadelphia were indicted for the Hanafi murders. Three were convicted in Superior Court. A fourth was acquitted after anothe rdefendant James H. Price, who had cooperated with the government, refused to testify against him.

Eight months later, Price was killeld in his prison cell. Three people - Griffin, another Hanafi massacre defendant, and a Black Muslim - were charged with his murder.

A sixth Hanafi defendant was tried and convicted separately but has since died from natural causes.