A 25-year-old Landover woman was shot to death Saturday night in an Arlington Towers apartment at a party that Arlington police said had "sexual overtones."

Ellen Dana Kisacky of 4809 Rockford Dr., Landover, was killed by one shot fired into her mouth from a .357 magnum revolver, police reported. Raymond Louis Urgo, 32, of 1121 Arlington Blvd., whom Kisacky had been dating for the past few months, was charged with murder.

Urgo, who had worked as a hairdresser for Bogart, Inc., a hairstyling establishment at 3108 M St. NW, was being held under $75,000 bond in Arlington jail, according to police, Urgo's arraignment, orginally scheduled for yesterday, was postponed until he can obtain a lawyer.

Police said Urgo notified them of the shooting shortly after the incident occurred in his second-floor apartment. He said the gun went off accidently, according to police.

Police said they bound Kisacky, a steno-clerk with the International Union of Bricklayers and Allied craftsmen in Washington, nude in Urgo's apartment. They said Urgo and one of two other women whom police said had attended the party also were present, fully-clothed, when police arrived on the scene.

According to Lt. Walter Hughes of Arlington's criminal Investigation Division, those who attended the party had participated in what he described as "group sex" immediately before the shooting.

He said the gun was apparently not used as a means of coercion.

Hughes said that the participants at the party had been drinking, but that "all concerned seemed to be within the normal range of their faculties."

Hughes also said he did not know if everyone at the party had participated in sex acts.

"I can't believe that she (Miss Kisacky) would be involved in something like that," said Charles Leckliter, who was married to her from 1969 until last year when they were divorced. "She was the type of person who when you met her, you knew you'd like her," he said.

According to her sister, Elizabeth Severn, Miss Kisacky returned three months ago to Landover to live with her parents, Adam and Erna Kisacky, after moving to Florida in 1972. She had done some modeling while away from home, Severn said.

"She was an extremely good worker and very cooperative. She had good secretarial skills and the ability to advance," said Michael C. Penn. Miss Kisacky's supervisor at the bricklayer's international. He said she had promoted from receptionist to steno-clerk two weeks ago.

In one of her last conversations with her sister, Miss Kisacky said she was beginning to realize that many of her friends "were not interested in her, in her best interests," Severn recalled.