In September of 1964 a small weight-reducing salon opened for business in Arlington, a couple of blocks away from the county courthouse and police station. Before the Leslie Olson Reducing Salon closed the next year, a curious assortment of people visited there -- not to shed pounds but to sample the services of two prostitutes. According to three people involved with the salon, regular customers included two nationally known U.S. senators, a cabinet secretary, assorted Virginia politicians and prominent local businessmen.

The visitors did not go unnoticed, because this business operated with the knowledge of -- and sometimes in the service of -- both the FBI and the Arlington County Police. A hidden tape recorded sometimes provided sound recordings of customers at play. Undercover agents noted both the identity of regular visitors and their peccadilloes, details which are still known to at least some members of the Arlington County Police.

What happened to the information collected about well-known Washingtonians is not known. Detective Theodore Terry, one of the Arlington detectives who monitored the parlor, says when political types began visiting he called the FBI. And he "assumes" some of the information garmered by observing the parlor helped fill the infamous private files of public people that FBI director J. Edgar Hoover reportedly kept.

Howard Richardson, the now-retired FBI agent who kept tabs on the parlor, denies he funneled sensitive personal information about politicians to his boss. "I didn't even know about the political names," says Richardson, who adds he had only "three or four" dealings with the woman who operated the parlor. Nevertheless, Arlington police interdepartmental memoranda indicate Richardson was kept informed.

The unusual little sex business in Arlington moved in May 1965 when Beate F. Fisher -- wife, mother, health salon founder, police and FBI informant -- closed the massage parlor and helped open a penthouse for prostitution in the Arlington Towers apartment complex. Along with politicians, says Fisher, came diplomats and military men who had the cash and inclination to frolic in bedrooms overlooking the Iwo Jima Memorial.

Pictures of Beate Fisher 15 years ago, when she was in her middle 30s, show a voluptuous woman with blond streaks in her hair. Today, living in Charlotte, N.C., where her husband works in the construction business, she frets about the weight she has gained. She speaks with a strong German accent -- she's a baroness of modest means who arrived in the United States in 1952 as the bride of an American Army man.

Fisher's husband left the military and moved to Washington in 1964. She had some experience working in a legitimate massage parlor in North Carolina, so with a little capital and a couple of steam cabinets, Bea Fisher opened her weight-reducing salon on the second floor of a frame house on Adams Street in Arlington.

"I was very idealistic in those days," she recalls. Two Arlington police officers visited her soon after she opened, and she remembers them telling her. "There are a lot of bad sexual activities in Washington." Fisher says they expressed the hope she'd report to them any customers who behaved strangly. Shortly thereafter she says FBI agent Richardson visited her with the same message.

Fisher says it was the police who encouraged her to hire the two young women who quickly changed the salon into a pay-for-sex establishment. But Theodore Terry, the Arlington detective for whom Fisher became a reliable source, says she "was a frustrated policewoman, a police freak who would just go out and dig up information -- we never paid her."

Whatever the truth, Fisher wasted no time in becoming a trusted informant to Terry, who remembers he was more interested in narcotics traffic than the celebrities who began to visit Fisher's establishment.

"That's why we brought in the FBI," recalls Terry, "because of some of the names coming in, political types crossing state lines."

According to Fisher, Terry, Arlington police memos and documents obtained from the FBI under the Freedom of Information Act, Fisher worked as an informant for about two years. She says she herself never engaged in sex for pay. Repeated several times in Fisher's FBI file is the notation that she was a trusted informant. During those two years she:

Led police to a Washington doctor performing illegal abortions.

Infiltrated and helped break up sex and dirty movie parties hosted by a Virginia car dealer.

Made drug buys and pointed out marijuana sellers.

Identified to FBI agents -- who apparently passed the information along to the IRS -- at least one individual supected of income tax evasion.

In the course of living her double life, Fisher was brutally beaten and dumped in her front yard by the backers of the penthouse sex operation who suspected Fisher of talking with police. She says she was threatened at the end of a pistol by another unsavory character who discovered the wire that led to the tape recorder on the back porch of her massage parlor.

She was arrested twice, first in March of 1965 in Arlington at her massage parlor on disorderly conduct charges. She paid a small fine. She says she never engaged in sex-for-pay. A year and a half later she was found guilty on one bad check charge and released on probation. It was partly that last arrest, partly a turn toward religion in her later life, and partly a decision on her part that law enforcement personnel overstepped their authority in spying on others that led to her decision to talk about her earlier life.

"I believed in systems, and I thought the FBI was doing something that was good," says Fisher. "I was rather stupid because, first of all, I really didn't have the right to judge other people. Which was what I was doing."

Fisher reached that conclusion after she left the Washington area in 1966. Angry that the FBI didn't acknowledge her role as an informant after her second arrest and subsequent brief jailing, Fisher returned to the life of a housewife in Charlotte, N.C. She worked as a nurse and dabbled in a church where members believe in psychic experiences and the existence of life on other planets. During the early 1970s she began reading news accounts of FBI "dirty tricks" and began reflecting on her short career. Now she has retained a Washington attorney to explore the possibility of filing a lawsuit; she'd like to ask the government to pay for her time as an informant and to eliminate her arrest record she maintains her undercover work caused.

The politicians Fisher, Terry and another former employe of the massage parlor remember as customers all prospered in their careers; no evidence exists that their lives were touched by the local police force's knowledge of their activities.

In North Carolina, Fisher says strange things still happen to her. She reported to the FBI that a man representing himself as a bureau official vistited her home and offered her cash not to discuss her past activities. Repeated inquiries to the Charlotte office of the FBI elicited no reason why agents didn't question Fisher about her claim that the bureau offered her cash to keep quiet. For several days earlier this year she returned to tell local police a bizarre story of having been drugged and ordered to keep quiet about her past life. Her house was in disarray, and her arm showed needle marks, but there was no further evidence to support her story.

For Fisher, it might take a lawsuit and the subsequent public airing of her hidden life to end the strange little sex story that began 15 years ago in Arlington.