As Marguerite Gras knows firsthand, "People don't want to be bothered about preventing crime until it hits them."

Gras has been the victim once too often. When she moved here in 1972, she thought Washington looked tame in comparison with Chicago and Philadelphia, where she had worked with youths in street gangs.

"I was walking home one February evening in 1974 and had my purse snatched by five neat, nice-looking kids," said Gras. "I was one of five people hit in the same hour on the same block."

Shortly after that Gras became co-chairwoman of the Capitol East Community Crime Council. She is still actively helping Capitol Hill neighborhoods organize to prevent crime.

Since 1975, some blocks on the Hill have been organized three or four times as residents come and go. Currently, there are 22 active groups in the council's area bounded by the Capital, the Anacostia River, the Southwest Freeway and H Street NE.

Residents meet with police one block at a time to set up "block-watch" programs and discuss ways of cutting off the rash of burglaries and more violent crimes.

Does it work? "If you're on the street, casing the block, and you know everyone is looking out the window and calling 911, you're going to go to another block," says Gras.

At regular meetings, residents draw a map of their street, pinpointing spots where "heavy hits" -- a number of break-ins or attempted robberies -- have been made. Patterns are established and "we can rapidly get to the true nature and method of the crimes," Gras says. "We have even matched up shooting in different district when the police couldn't."

First District police Capt. Gary Abrecht says the block-watch programs are "certainly successful in the short term. But it's been shown that it's hard to maintain the citizen's interest. Once the immediate problem is solved, people tend to become lax."

This month, Abrecht says, the police force will give awards to two men involved in a recent crime-stopping effort. "A truck driver was coming up Eighth Street, saw three juveniles about to snatch a lady's purse and yelled to a Marine jogging that way. He turned his truck around and, while someone else called the police, both men caught the kids and held the suspects until police responded.

"Now, some people might call that vigilantism, but we say it's laudable to go to the defense of a fellow citizen. The next step -- stringing 'em up in a tree -- isn't. But citizen's arrests are lawful and to be encouraged."

Gras points out that tactics for neighborhood groups vary, "but the theme is 'don't make it easier for the criminal.'" Safety measures are tailored to the specific block, in close cooperation with police, and word is spread through meetings, parties and alley clean-up projects. Among the recommended precautions: write down a description of anyone who appears to be loitering, exchange phone numbers with neighbors, come home from work at odd hours to check on the area, take photographs of strangers outside from a safe vantage point indoors, put decals on windows to indicate police identification of household property and make sure house members are plainly visible.

Most block activists became involved after they suffered personal losses or assaults. Peter Abel, a physicist with the National Earth Satellite Service, started orgainizing his block when his house was broken into -- two days after his neighbor's house was burglarized.

"They took $2,000 worth of goods in 10 minutes," Abel says. "It's a shock the first time 'round. I decided to contact as many people as possible and to combat the wave of crime esclating across the city." So far, he's arranged three meetings: 40 people attended the most recent one in early December. Council woman Nadine Winter sat in on that meeting.

"The block-watch groups have done more to serve as a deterrent to crime than anything we've done," Winter says. She's making an effort to coordinate and eventually secure funds for the 22 active groups in her district, starting with a joint meeting the first week of February.

Abel and his neighbors are orgainizing a block watch, working on the maintenance of street lights, setting up systems by which trusted neighbors know when others aren't home and establishing the identity of people who hang around street corners.

And then there are local organizers such as Martha Weston, a Georgetown Day School teacher,whose work to prevent crimes isn't necessarily a result of being a victim. Weston was active in local crime-prevention groups for three years before her home was burglarized. She says she is "a great fan of organizing blocks and neighborhoods. I feel very safe here." Weston said the outpouring of sympathy from her neighbors after her house was broken into reminded her of "growing up in small-town Illinois. It's a great support network," she says.

"Living in a city, you really can't be autonomous."