Irene Yaskovich was sitting at the dining room table in her Wheaton home late Thursday night, rolling a fresh piece of paper into her typewriter, when three bullets blasted through the window behind her in rapid succession, one of them piercing her back.

The 53-year-old civic activist and mother of three slumped to the floor and crawled several feet into the bedroom, where she collapsed. She was dead within a half-hour.

Up and down the streets near the Yaskovich home at 1817 Arcola Ave. families awakened and wondered whether it could have been the sound of gunshots that echoed through their quiet, middle-class neighborhood.

"My sister thought it was firecrackers, but I knew it wasn't," said Trish Oliverio, 17, who lives several blocks away. "But in this area, I didn't think this could happen."

Oliverio's shock was reflected yesterday in the faces of the neighbors who gathered outside the Yaskovich house, watching detectives as they roamed in and out of the one-story, clapboard structure, searching for clues in the 11:30 p.m. murder. The peoplee had never seen anything quite like this before on Arcola Avenue, where crimes more serious than burglaries seldom occur.

About an hour after the Yaskovich shooting, police said, several shots were fired by an unidentified person into the front of a house in the 7600 block of Rosdhu Court in Chevy Chase. No one was injured in that shooting. Police said they are investigating to find if the incidents were connected.

Montgomery County police said yesterday they had no suspects, motives or clues in the shooting of Irene Yaskovich, although they believe the weapon used in the shooting was an automatic handgun.

Relatives and neighbors were puzzled yesterday about why somewone would have killed Yaskovich. "I don't know why it happened," said Yaskovich's daughter, Janice. "Nobody knows why it happened."

Police said the slayer apparently walked to the back of the house through Wheaton Woods, a park adjacent to the Yaskovich backyard, then aimed at the picture window, firing at least three times, and fled through the woods. Yaskovich was visible through the unshaded window, police said.

One of the bullets went through the house, hitting the front wall, knocking down plaster, and creating a hole about six inches inn diameter.

Yaskovich was in the house alone when she was shot, police said.Her body was discovered shortly after midnight, about 45 minutes after the shooting, by her 16-year-old daughter Carol, who had just returned home from work.

Yaskovich's husband, Harold, a former Air Force lieutenant colonel, returned to the home yesterday from Hampton, Va., where he had been doing free-lance consulting work at Langley Air Force Base.

Suntanned and carrying a brown leather bag, he said he felt "sheer shock" when he learned from police yesterday morning that his wife had been killed.

"My wife stayed home 99 percent of the time. Whe didn't drive and she was always very busy with work in the garden," he said. "She was not that involved in socializing to the far reaches of the neighborhood, but she did a lot of work with civic associations and community groups."

Neighbors remember Irene Yaskovich as someonw who fought for more street lights on Arcola Avenue, who fought against subsidized housing planned for the area around Sligo Creek, and who was always showing up at their doors with petitions.

Yaskovich was working this year as a part-time volunteer in the congressional campaign of Republican Newton Steers. She often went to the Steers campaign's Bethesda headquarters, where she picked up mailing lists of names to take home to be typed on the mailing labels. She was one of more than 40 "mid-level volunteers," according to Steers' campaign chairman Howard Denis.

"She was dependable, one of those people you could always count on to do something," said Denis. "No one is thinking straignt around here, we're completely shocked."

Yaskovich attended Steer's victory celebration the night he won the Republican Party primary last month. During his 1978 campaign, she also worked at the then congressman's D.C. office as a volunteer. "She was a nice, sweet person, very energetic and concerned about community issues," said Bobbi Advancena of the Steers campaign committee.

Yaskovich was also an ardent supporter of state Del. Idamae Garrott, who she first called on a decade ago when she was having a problem with pigeons in her yard. "I'm so shocked I don't know what to do," Garrott said. "I'm saddened and shocked, she was an attractive woman full of vitality."

Leah Gelb, who lives across the street from the Yaskovich home, called her "a puzzle of a woman."

"She was eccentric," said Gelb. "I'd see her at every accident on Arcola Avenue. She'd yell at the cops and say: 'Why don't you put a sign up? Why don't you put radar up?' She was popular, everyone knew her, but she was not liked. Somebody must have had it in for her, someone arguing with her or petitioning against her."

Several houses away, Helen Marzo said she remembered Yaskovich as the woman who would come nto her back, uninvited, and pick tomatoes. "She'd say, 'Your husband was out so I thought I'd pick these. I'm just picking the rotten ones,'" said Marzo. "Then I'd walk away and leave her there."

The Yaskovich family owned and lived in two houses -- the one in which Irene Yaskovich was killed and the red brick house next door, at 1815 Arcola Ave. Harold Yaskovich said yesterday that the family purchased the second house about three years ago, because it was larger than the home they had lived in for 25 years.

Neighbors said yesterday that the family that had previously lived in the house at 1815 Arcola Ave. moved in part because they didn't get along with Irene Yaskovich.

"She'd always be peeking through the fence or yell at them if they were cooking steaks out back, or hammering," said Gelb.