BONN, JUNE 15 -- American victims of the 1985 TWA jet hijacking were shown a suspected Lebanese terrorist today and asked to identify him as one of the men who took them hostage and murdered a passenger, West German officials said.

Chancellor Helmut Kohl's top security adviser, Horst Teltschik, said results of the session could determine how West German authorities handle the case of suspect Mohammed Ali Hamadei.

Teltschik's comments indicated that West German authorities were counting on the American witnesses to provide the necessary evidence to try Hamadei in this country for murder and hijacking.

The United States has asked West Germany to extradite Hamadei, but it is widely believed here that Bonn plans instead to try him in West Germany for the same murder and air piracy charges that he would face in Washington.

West Germany is reluctant to extradite Hamadei because of concern for two West German businessmen who were kidnaped in Lebanon shortly after Hamadei was arrested at Frankfurt airport in January. The kidnapers have treatened to kill the hostages if Hamadei is extradited.

The U.S. Embassy and West German spokesmen declined to comment on the results of the identification session or to provide other details. They were understood to be concerned that publicity could endanger the American witnesses.

Teltschik, speaking to foreign journalists, said the government had not ruled out extraditing Hamadei. He said the identification session would make clear how much evidence is available against the suspect and would thus help determine what charges he would face.

Without material provided by the United States, West German judicial authorities would have enough evidence only to try Hamadei for illegal possession of explosives and carrying a false passport. He originally was detained on those charges, but a fingerprint check allegedly identified him as one of the terrorists who staged the TWA hijacking in which U.S. Navy diver Robert D. Stethem of Waldorf, Md., was murdered.

A Border Guard helicopter transported Hamadei from a Frankfurt prison to a judicial office in Wiesbaden for a meeting of about three hours with the U.S. hijacking victims, West German television said.

U.S. Attorney for the District of Columbia Joseph E. diGenova, who would prosecute Hamadei if he were extradited, escorted the witnesses here and also brought physical evidence against the suspect, judicial sources said in Washington. DiGenova planned to seek to persuade the West Germans to extradite Hamadei, they said.