BONN, AUG. 16 -- Prosecutors indicted three West German computer hackers today on charges of supplying the Soviet KGB intelligence service with data obtained surreptitiously from U.S. and other Western military, research and commercial computer systems. The indictment marked the first time that hackers -- private citizens who gain unauthorized access to computers, usually just for the sport of it -- have been accused of espionage. The hackers are charged with making about 25 deliveries of data to a KGB agent in East Berlin over a period of more than two years, beginning in September 1986, in exchange for payments totaling $46,000, the Federal Prosecutor's Office said in Karlsruhe. The three suspects allegedly supplied the Soviets with "information from and passwords to a large number of computer systems in the research, industrial and military area," the prosecutor's office said. The hackers, who penetrated computer systems in 12 countries and Hong Kong, also are charged with selling the Soviets computer programs and a copy of a computer security system. The indictment, which was handed down five months after the case became public, confirmed that investigators believe they have enough evidence to support spying charges against the hackers. Prosecutors previously were uncertain whether they would be able to show that the hackers had delivered data to the Soviets. The prosecutor's office identified the three suspects, who face prison sentences of up to five years if convicted, only as Markus H., 28, and Peter C., 35, of Hanover, and Dirk B., 30, of West Berlin. It declined to provide their full names to protect their privacy. It appeared very likely, however, that "Markus H." is Markus Hess, a computer programmer and hacker who previously was identified by prosecutors as a leading suspect in the investigation. Hess was the hacker whose electronic trail was monitored from August 1986 to the spring of 1988 by U.S. astronomer Clifford Stoll, whose suspicions were aroused because of a 75-cent discrepancy in his billing records when he was working at Lawrence Berkeley Laboratory in California. Stoll's computer sleuthing put U.S. and West German investigators on the track of Hess and the rest of the hacker group, and led to their detention in March. Hess was released at that time because of lack of evidence. Reached by telephone at his home in Hanover this evening, Hess answered "maybe" when asked whether he was the "Markus H." indicted today. He declined to answer further questions. The other two suspects have been in jail since March, although only "Peter C." previously had been held on suspicion of espionage. A former casino croupier, "Peter C." is charged with having met with a KGB agent known as "Serge" who worked in a Soviet trade mission in East Berlin, the prosecutor's office said. "Dirk B." has been imprisoned not for spying but on a separate charge of deserting from the Army. Prosecutors originally said eight West Germans were suspected of having participated in the hacker ring. One of them, Karl Koch, died in May, apparently a suicide. He and a second hacker, identified only as "Hans H.," had cooperated with investigators. The prosecutor's office did not identify any of the computers that were penetrated but said they included systems in the United States, Japan, West Germany, Britain, France, Italy, Norway, Austria, Spain, the Netherlands, Switzerland, Canada and Hong Kong. It also said the full extent of the information provided to the KGB was not known. A West German television report said the hackers penetrated a U.S. Defense Department personnel system computer known as Optimus, as well as computers at the Jet Propulsion Laboratory at Pasadena, Calif., and at the national Lawrence Livermore Laboratory in Livermore, Calif. The Bonn government said in March that the breakup of the ring had been "a severe blow" to the KGB and that the case revealed "a new dimension" in East Bloc intelligence gathering. But U.S. and West German officials said at the time that the hackers had gained access only to the periphery of the computer systems that they tapped and that they had obtained sensitive but not top-secret data.