In an atmosphere that was taut with the defendants' solidarity and the government's heavy security, 12 Hanafi Muslims went on trial yesterday in D.C. Superior Court on charges of murder, armed kidnapping and related offenses arising from the seizure of 149 hostages in three downtown Washington buildings last March.

A police helicopter whirred overhead as a prison can brought the defendants from D.C. Jail to the court house at 6th and E Streets N.W. The van was escorted by police squad cars that cleared the way with their sirens.

All persons entering the courthouse had to identify themselves and then pass through metal detectors. All packages were searched. Persons entering the second-floor courtroom had to again go through these procedures, U.S. marshals stood guard around the courtroom and in the rooms and corridors outside.

Judge Nicholas S. Nunzio took the bench about 10:15 a.m. and thus began woth elaborate protocol one of the largest trials and one of the most publicized cases in the city's history.

Almost the first order of business was an objection from several defense attorneys about the arrangement of the L-shaped table around which the defendants and their lawyers have to sit. The arrangement was changed to the satisfaction of the lawyers during the luncheon recess.

After that, there were further requests that cushions be provided for the chairs, that the dietary laws of defendants observing the Hanafi Muslim faith be met by court personnel, and "that the cellblock immediately behind the courtroom be kept clean.

Judge Nunzio instructed court perssonel to satisfy these requests as far as possible.

Apart from these housekeeping matters, the day was given over to arguments on a series of defense motions designed to ensure that the government follow the letter as well as the spirit of the law in trying to convict the Hanafis.

Today, a record panel of 650 prospective jurors is scheduled to be in court. From their number, 12 jurors and 12 alternates will be selected. The jurors and the alternates will be sequestered throughout the trial.

Each member of the panel will be asked to fill out a questionnaire. The questionnaire asks, first, whether the juror can undergo lengthy sequestration. Then it asks whether he or she has read or heard of the case. Finally, it asks whether the prospective juror could reach a verdict based on the law and the evidence presented in court even though he or she may have read or heard of the case.

The answers will be fed into a computer. By end of today, it is hoped that at least 200 members of the panel will remain after the initial computer screening. The jurors and alternates will be picked from this group after further detailed questioning. Several of these questions, which have been submitted by defense counsel, concern race and religion.

Yesterday's first defense motion was to throw out the 32-court indictment on the alleged grounds that one of the two prosecutors, Assistant U.S. Attorney Martin J. Linsky, had advised one of hostages not to talk to defense attorneys.

The man in question was Alan F. Grip, special assistant to City Council Chairman Sterling Tucker. Grip one of those allegedly held by the Hanafis at the District Building, where Maurice Williams, 24, a reporter for radio station WHUR, was shot to death.

D.C. City Council member Marion S. Barry was shot and wounded at the District Building. Several other persons were injured there and at the international headquarters of B'nai B'rith, 1640 Rhode Island Ave. NW, and at the Islamic Center, 2551 Massachusetts Ave., NW, the other two sites where takeovers occurred.

Grip testified yesterday that a defense attorney asked to interview him. He said he reported this to Linsky and that he asked the prosecutor if he was required by law to talk to the defense.

Under questioning by Assistant U.S Attorney Mark H. Tuohey III, who is prosecuting the case with Linsky, Grip said Linsky had advised him that he was not required to talk to the defense, but that he was free to do so. Grip said he had decided not to after seeking private legal advice.

Judge Nunzio denied the motion. Had he granted it, all 12 defendants would have gone free.

This is because it is against the law for a prosecutors to deny to the defense access to witnesses who may be of assistance.

It emerged during argument that only of those held hostage at any of the three sites has agreed to be interviewed by the defense.

This appeared to typify the problems of the defense attorneys, given the determination of the Hanafis to go on trial with Hamaas Abdul Khaalis, 54, alleged leader of the takeovers.

Several attorneys filed motions for separate trials. These were withdrawn at the requests of their clients, or overruled by Judge Nunzio in accordance with the wishes of defendants, as was the motion to move the trial to another location.

In this situation, the defenses appear to be limited to putting the government to the test on matters of procedure and proof. There has been no hint thus far of any "positive" defense - one based on defense testimony.

This is not unusual in criminal cases. All defendants are presumed to be innocent unless they are proved guilty according to law. The defendant never is required to prove his or her innocence. The government always is required to prove guilt.

The indictment charges that Hamaas and the other Hanafis carried out the takeovers in an effort to compel the government to turn over to them persons convicted of murdering seven Hanafis at the Hanafi headquarters at 7700 16th St.NW in January 1973. Khaalis said during the sieges that he wished to mete out his own justice to those who had been convicted. All seven victims were members of Khaalis's family.

The Black Muslims convicted of the massacre were tried in the same courtroom where the Hanafis now are on trial. A final defendant in the massacre case in scheduled to go on trial in Superior Court on June 30.

Among the motions yesterday was one by Harry T. Alexander, a former Superior Court judge who is representing Khaalis.Alexander moved that he be addressed as "Judge" in the courtroom.

Not to accord him this title could be "evidence of racial discrimination," said Alexander, who is black. He said two former white judges had been called "Judge" in courtrooms when they returned to private practice.

Nunzio overruled him, as he had in a similar situation last week. Nunzio said he would be "the only legal umpire" during the trial and in the presence of the jury.

Besides Khaalis, who formerly was known as Ernest Timothy McChee, the defendants are: Abdul Adam, also known as George W. Smith; Abdul Latif, also known as Carl E. Roper; Abdul Shaeed, also known as Marvin Sadler; Abdul Salaam, also known as Clarence White; Abdul Hamid, also known as Hilvan Jude Finch: Abdul Razzaaq, also known as Nelson McQueen Jr. and as Norman Lee; Abdul Rahman, also known as Clyde Young; Abdul Al Qawee, also known as Samuel Young; Abdul Muzikir, also known as Marquette Anthony Hall, and Abdul Nuh, also known as Mark E. Gibson. CAPTION: Picture, Abdul Aziz, son-in-law of Hamas Abdul [WORD ILLEGIBLE] wife and [WORD ILLEGIBLE] AP