A homosexual prostitution ring is under investigation by federal and District authorities and includes among its clients key officials of the Reagan and Bush administrations, military officers, congressional aides and US and foreign businessmen with close social ties to Washington's political elite. Reporters for this newspaper examined hundreds of credit-card vouchers, drawn on both corporate and personal cards and made payable to the escort service operated by the homosexual ring. Among clients who charged homosexual prostitutes services on major credit cards over the past 18 months are Charles K. Dutcher, former associate director of presidential personnel in the Reagan administration, and Paul R. Balach, Labor Secretary Elizabeth Doles political personnel liaison to the White House. Members of major news organizations also procured escort services from the ring, credit card documents show. These include Stanley Mark Tapscott, who was an assistant managing editor of The Washington Times. Before joining The Times, Mr. Tapscott worked for the Office of Personnel Management in the Reagan administration. A major concern, said the former official with longtime ties to top-ranking military intelligence officers, was that hostile foreign intelligence services were using young male prostitutes to compromise top administration homosexuals, thus making them subject to blackmail.