The strip of Ninth Street NW south of Mount Vernon Square traditionally has been a favorite "pick-up" spot for Washington area homosexuals. In the last year that strip has taken on a dangerous cast as eight homosexual men known to frequent the area have been found stabbed, shot or bludgeoned to death in their homes, cars or apartments.

In each of the murders, which are still unsolved, police believe the victim picked up his killer on the "hustler" trade there and invited the assailant to his home. Since September 1977, one victim was found slashed to death in his apartment, four were found beaten, two had been shot, and one man was found strangled in his car parked near the Chesapeake House, a restaurant on Ninth Street NW that is a gathering place for homosexuals.

The eight victims were all far older than the young men, often teen-agers, who openly attend homosexual-sponsored gathering looking for partners. One victim was 60 years old, two were in their 50s, two were over 40 and two others were over 38.

Members of the homosexual community say it is not a coincidence that the victims were in an older age category. That fact, they say, underscores the older homosexual's uneasiness with the new, open "out-of-the-closet" attitude of younger gay men.

The men who frequent the Ninth Street area - and the homosexual haunts there such as the Chesapeake House and the Eagle bar - are in many cases professionals, lawyers, teachers and government workers who feel that any open display of their homosexual feelings could lead to the loss of a job or the break-up of a marriage.

One victim, for example, was an administrator for the Office of Economic Development. While police are listing his death as the eighth homosexual murder, his family still refuses to believe he was a homosexual.

In another slaying, the victim's family refused to believe that the man was a homosexual, despite the fact that he was found strangled in his car parked behind the city's best-known gay bar.

That victim - a 50-year-old Virginia man with a wife and four children - typifies the case of the homosexual who has still not come "out of the closet." The wife refuses to believe police detectives when they insist the man was homosexual.

It is the very fact that many of the victims chose to hide their homosexuality that homicide investigators are having a difficult time finding leads in any of the cases.

In one case, a heterosexual friend of the slain homosexual manager of the Chesapeake House posted a $5,000 reward in the Blade, a homosexual newspaper, asking for any information to help solve his friend's murder. Despite the large sum offered as reward, homicide detectives say they received fewer than a dozen telephone calls, and none of the callers had any substantial information.

"Any time you are conducting a homicide investigation where there are no witnesses, you're starting at a disadvantage," said Captain Arif Mosrie of the homicide squad. "Very often in homosexual murders, we don't find the body until two or three days later because the murder usually takes place in private. Those two things alone make the investigation different than the routine murder."

Despite the similarities in the eight murders - and despite rumors in the homosexual community - detectives do not believe a single killer is responsible for the slayings. There is no special homicide team assigned to the homosexual murders, and the eight open cases have been scattered among the homicide detectives like routine murders.

For the most poart, investigators admit that they are up against a wall in trying to solve any of the slayings. They must piece together the last hours of men who did their best to conceal their movements and their identities from their families and their closest companions.

That same problem hampered investigators in the Cinema Follies fire of October last year. Nine persons were killed in the blaze that destroyed that homosexual club in Southeast Washington, but since most of the victims carried no identification and many concealed their homosexuality, it took investigators four days to identify all the victims.

Homicide detectives, asked to pinpoint the primary difficulties in solving homosexual murders, said many, if not most, homosexuals are still "in the closet," and it is hard to find anyone to admit knowing a homosexual murder victim: homosexuals tend to keep their companions secret, even from other homosexuals: homosexuals are now scattered all over Washington and not confined to the "gay strip."

Police also said that in homosexual 'lovers' quarrel' that end in murder, the perpetrator often feels justified. Police point out that not all homosexual murders are "lover's quarrels" but some are routine burglaries and robberies.

Still, in the homosexual community at least, the thought of eight unsolved murders - all where the victim picked up his killer as a "hustler" - conjures the immediate image of a "Son of Sam" type killer taking out a bloody vengeance against homosexuals in Washington.

"It could be a hustler gone crazy or a straight person trying to act some kind of a vendetta," one homosexual man said.

Even those in the Washington gay community who do not subscribe to the "single killer theory" believe that there is a common "mentality" at work in the slayings - an angry, violent blacklash against the new visibility of gays and gay organizations, and an outgrowth of the Anita Bryant crusade and the Dade County, Fla., repeal of homosexual rights laws.

Washington has one of the nation's strongest laws protecting homosexuals from discrimination in housing, employment and public accommodations. It also has pending a voter-approved referendum and recall process. The possibility that this might be used, as in Dade County, to repeal homosexual rights has sent chills through the homosexual community here.

Legislation to activate the referendum process is pending in the City Council's government operations committee. It contains no provision that would prevent a vote to curtail homosexual rights, or any other human rights. Homosexuals are pushing hard for such a provision, but it has run into legal problems, and the bill is stalled.

"People generally feel threatened by the visibility of homosexuality," said the Rev. Larry Uhrig of the Metropolitan Community Church. "The fear, the anger, the regret is being vented in violent acts."

Uhrig believes one of those "violent acts" was the Oct. 2, 1976, slaying of Ronald J. Pettine, whose nude, battered body was found in the woods near the Iwo Jima memorial in Arlington, a widely known meeting place for homoesexuals.

Michael G. Simonean, the 17-year-old who was convicted in June of Pettine's death, had testified in his own defense that the night of the murder he set out to "smack around a few queers."

While Uhrig said he "would not be surprised if one person were involved in more than one" of the recent homosexual murders, he believes "it's more of (an anti-homosexual) mentality being fed" rather than any orchestrated assault on Washington-area homosexuals.

According to Robert Davis, vice-president of the Gay Activist Alliance, changing that mentality to stop crimes against gays is "talking about something a lot more complicated" than the eight recent murders.

For the short term, the Gay Alliance and the homosexual community are exploring ways to protect Washington area homosexuals from the recent spread of violent acts.

In their regular meeting two weeks ago, a special committee of the alliance proposed - and the alliance accepted - endorsement of a series of safety precautions to recommend to owners of bars where homosexuals are known to meet.

The proposals, borrowed from a similar list prepared by the D.C. Feminist Alliance, include: requesting security escorts for homosexuals on busy nights; car patrols around parking lots; improved street lighting outside bulletin boards advertising the bar's increased security measures, to deter attackers on advance, and, finally for bar owners to provide time and space for self-defense demonstrations for gay patrons.