VIENNA, FEB. 9 -- Four weeks' interrogation of a woman suspected of planting a terrorist bomb in a West Berlin discotheque in 1986 has failed to yield sufficient evidence to charge her with murder, West Berlin judicial spokesman Volker Kaehne said today.

Police are searching for a second woman who, according to witnesses, sat with suspect Christine Endrigkeit near the spot in the Labelle discotheque where the bomb exploded later in the evening and killed three persons, including two U.S. servicemen, Kaehne said in a telephone interview.

Endrigkeit has said since her arrest on Jan. 11 that she never was in the discotheque or that her heroin addiction prevents her from remembering clearly, Kaehne said.

U.S. warplanes raided Libya after the U.S. administration charged that the Libyan government ordered the Labelle bombing. But prosecutors suspected that Endrigkeit may have acted on orders of convicted Arab terrorist Ahmed Hasi, who was found by a court to have staged another West Berlin bombing with help from Syrian officials.

Endrigkeit's phone number was found in Hasi's personal telephone book, Kaehne said.

When shown pictures of Hasi early in her interrogation, Endrigkeit said she had seen him in the past, Kaehne said. Later, however, she said that she did not know him or that she could not remember, he said.

When police recently brought Hasi and Endrigkeit face to face, they both said that they did not know each other, Kaehne said.