A former head of the Pagans motorcycle gang and another man were killed and a third person was seriously wounded Tuesday night in a Fairfax City shootout.

The two men killed in the gun battle had entered an apartment there, armed with revolvers and anxious to confront a man they believed had destroyed one's marriage, police said.

Moments later, after what neighbors described as two separate bursts of gunfire, three people lay wounded. Police said yesterday they still were unable to say who fired the first shot in the incident, but said that the third man also had been armed with a handgun.

Fairfax County prosecutor Robert F. Horan Jr. yesterday identified one of the dead men, Frederick F. Burhans Jr., 35, of 2424 N. Roosevlet St., Arlington, as the 1975 president of the Pagans motorcyle gang, a group that has had frequent brushes with law enforcement authorities in Virginia.

The other dead man was identified by police as William Vincent Sitko, 28, of 255 Cabbell Drive, Manassas Park. Officers said Sitko, a house painter by profession, had been despondent over the breakup of his marriage.

The man Burhans and Sitko confronted, David Wayne Keiser, 29, of 3915 Lyndhurst Drive, was listed in serious condition last night at Commonwealth's Doctors Hospital in Fairfax. He suffered leg and chest wounds in the shooting, hospital officials said.

Police Sgt. Samuel Ellis said Sitko and Keiser apparently "had had an earlier disagreement. There was some bad blood between them."

Sitko had been separated from his wife for a month and had become convinced that Keiser was a reason for the estrangement, according to a Manassas Park neighbor.

Police said Sitko and Burhans were allowed inside the apartment. After a brief exchange of words with Keiser, who was seated on a couch in the apartment, the shooting started, said Sgt. Ellis. "About five to seven shots were fired."

"Sitko had apparently gone to the apartment, banging on the door, two weeks ago, but Keiser was not home," Ellis said. "Sitko had been after Keiser for about that time."

A couple in an apartment next to Keiser's yesterday reported hearing "four or five gunshots while we were watching televison. Then there was a sound of a body falling. then there were two or three more shots. Then someone was in the hallway screaming for an ambulance."

Burhans died instantly of a head wound, Ellis said. Sitko was rushed to the shock trauma unit of the Washington Hospital Center where he was pronounced dead at 12:50 a.m. also from a head wound, a spokeman said yesterday.

Keiser's girlfriend, Rhonda Lee Lonigro, 22, and her sister, 21-year-old Robin Lee Payne, had been living with Keiser at his apartment with their two small children, according to Ellis. Both women were present during the shooting and said that Lonigro answered the door and that Keiser told her to let the men inside, the officer said.

Also in the living room of the apartment was Keiser's 25-year-old brother, James Richard Keiser of Manassas. Sitko's estranged wife was not in the apartment, located off Main Street near Fair City Mall, during the shooting according to police.

Burhans, a former member of the motorcycle gang that once bragged in 1967 that it would "take over the East Coast the way the Hell's Angels took over California," apparently did not fire a shot, according to Ellis. Burhans' revolver was never fired, Ellis said.

No charges had been filed yesterday in the killings, which Fairfax City police said were the first in the small suburban jurisdiction in 16 months.