Rep. Jon Hinson, a Mississippi Republican who narrowly won reelection last year after acknowledging he had been to a homosexual club here, was arrested and charged yesterday with committing sodomy in a public restroom in the Longworth House Office Building.

Hinson and a Library of Congress clerk were arrested after Capitol police said they observed the two men in the restroom, which had been reported in complaints to police as a meeting place for homosexuals.

Two other men were arrested about two hours earlier in the same restroom, located on the fourth floor of the building, which had been under surveillance for about a week, police said.

Hinson, 38, a conservative second-term congressman for southwest Mississippi, announced at a surprise press conference last summer that he had been one of the survivors of the fatal 1977 fire at Cinema Follies, a Southeast Washington club and theater had been accused of "an abscene act" on the grounds of the Two Jima Memorial, a widely known after-dark gathering place for some homosexuals.

He told the press conference that he and his wife, Cynthia, hoped to "put these incidents behind us -- finally." Hinson and the other three suspects arrested yesterday were not available for comment. Hinson was released on $2,000 bond and scheduled to appear with the other three in D.C. Superior Court this morning.

The other three suspects were identified by police as library clerk Harold Moore, 28, of Oxon Hill, who was charged with sodomy; and Kerry Lee Jones, 36, an employe of the Democratic Study Group and resident of the 1600 block of A Street NE, and Jettom Scott Douglas, 28, an independent lobbyist and resident of the 4800 block of Connecticut Avenue NW.

Jones and Douglas were arrested about 11:15 a.m. in the restroom and also charged with sodomy.

Deputy Chief Gilbert Abernathy said Capitol police were told last week that some homosexual men had been using the public restroom for sex. Abernathy said a team of officers, five or six men in civilian clothes, have been keeping the facility under "physical observation" without the use of cameras, and said it was set up without any knowledge of who might be arrested. He said the operation was cleared by the Capitol Police legal counsel, and the U.S. attorney's office was informed of it.

Abernathy said the two pairs of men were observed separately in "the common use" areas of the restroom, adjacent to private stalls. He said "a signal was given" and officers went into the restroom to make the arrests. He declined to discuss further details except to say "it is an ongoing operation."

Prosecutors said the charges against the four men are felonies and if convicted each could face a sentence of 10 years in jail and $10,000 in fines. Sodomy by either homosexual or heterosexual adults is illegal in the District. Few such arresta are made and those that are generally follow specific complaints to police about such public activity.

Abernathy, a 19-year veteran of the force, said the arrests were the first public sex arrests made on the Capitol grounds in his memory.