Twelve Hanafi Muslims formally pleaded innocent yesterday to murder, armed kidnaping and other charges arising from the takeover last March of three buildings in the District of Columbia and the holding of 149 hostages.

The pleas were entered as the 12, including Hanafi leader Hamaas Abdul Khaalis, 54, were arraigned before Judge Nicholas S. Nunzio of D.C. Superior Court on an indictment returned last week by a federal grand jury.

Of the 32 counts in the indictment, 29 carry maximum penalties of life imprisonment.

Nunzio set the trial for all 12 defendants for May 31. Assistant U.S. Attorney Martin J. Linsky, one of the two prosecutors, said the case could take from one to two months to try.

Khaalis is entitled to a trial by May 31 because of the provisions of the law under which he has been held in D.C. Jail since March 31. He was incarcerated on that date for allegedly violating the conditions under which he has been released without monty bond on March 11 pending possible grand jury action.

City and federal officials agreed to permit Khaalis to go free without bond in order to obtain the release of the hostages. A total of 149 persons were held by the Hanafis on March 9 when they took over the international headquarters of B'nai B'rith, the Jewish service organization, at 1640 Rhode Island Ave NW; the District Building, at 14th and E Streets NW, and the Islamic Center, at 2551 Massachusetts Ave. NW.

Maurice Williams, 24, a reporter for radio station WHUR, was shot to death during the takeover of the District Building D.C. City Council member Marion Barry was wounded there and several other persons were injured there and elsewhere.

The sieges ended in the early hours of March 11. By that time, the Hanafis had released 10 of their hostages for medical or other reasons. When the sieges ended, that remaining 139 were released.

Later that day and in the following week, Khaalis's 11 codefendants were jailed in lieu of $50,000 or $75,000 bonds. All remain in jail.

According to the indictment, the Hanafis began the takeovers to try to compel officials to turn over to them the persons convicted of killing seven members of Khaalis's family in January, 1973. They also sought to halt the showing in the United States of the [TEXT OMITTED FROM SOURCES]

The indictment charges all 12 defendants with conspiracy to attain these ends as well as with murder, armed kidnaping, assault with intent to kill, and other offenses. Under the conspiracy theory, all 12 are equally responsible for these alleged acts.

Yesterday's arraignment, which lasted 30 minutes, was ordtrly and businesslike. Judge Nunzio appointed attorney's for five of the defendants whose original court-appointed counsel had asked to be excused.

The purpose of an arraignment is to advise accused felons of the charges against them an opportunity to enter formal pleas of guilty or innocent.