The jury sitting in judgment of 12 Hanafi Muslims charged with murder and kidnapping in the takeover of three Washington buildings last March heard instructions on the law of conspiracy yesterday and shortly thereafter recessed its deliberations until today.

The two men and 10 women on the panel also requested that tapes of telephone conversations that are part of the evidence in the case be played for them. Judge Nicholas S. Nunzio of D.C. Superior Court ordered that this be done and then gave a requested explanation of conspiracy.

The taped telephone conversations and the law of con-piracy go to the heart of the case, which has been in trial since May 31.

The prosecution contends that the tapes prove that all 12. Hanafis were members of a conspiracy, the ultimate purpose of which was to force the government to turn over to the Hanafis five Black Muslims convicted of murdering in 1973 seven members of the family of Hamass Abdul Khaalis, 55, alleged leader of the group.

A second purpose was to bar the showing in this country of the film "Mohammad. Messenger of God" on the grounds that it is sacrilegious, according to the charges.

The government contends that the Hanafis took 149 hostages for these purposes at the international headquarters of B'nai B'rith the Jewish service organization, at 1640 Rhode Island Ave. NW: at the Islamic Center at 2551 Massachusetts Ave. NW, and at the District Building at 14th and E Street NW.

One person, Maurice Williams, a 24-year-old radio reporter, was killed at the District Building. Several others were injured there and elsewhere.

Since all 12 defendants are charged with conspiracy, all 12 also are charged with murder. This is because all members of a conspiracy can be held responsible for any act done to fulfill the purpose of the conspiracy.

The defense contends that at least two of the tapes replayed for the jury yesterday show that there was no conspiracy, at least as far as the events at the District Building are concerned.

If the jury decides that the District Building was outside any conspiracy, then the murder changes against the 10 defendents who were not present there fail.