For the past decade, Laura Ahearn, executive director of Parents for Megan's Law and the CrimeVictim's Center, has been painstakingly compiling information about sex offenders and distributingit - first by hand, then by e-mail - to their neighbors, including updates like a new car or newscar. Last week, her nonprofit advocacy group received a $593,000 federal grant to take theirproject national, using the sharp new mapping program that enables a computerized tour. After aquick aerial survey of Long Island and the sites where its 1,200 registered sex offenders reside,Ms. Ahearn used her computer's mouse to swoop down on the Nassau County village of Hempstead,dotted with 50 icons resembling pushpins: green for Level 2 offenders, blue for Level 3. She headedeast over Brentwood in Suffolk County, home to about 60 offenders, and zeroed in on the thickestcluster: the Gordon Heights section of Coram, with 69 pushpins, more than a dozen crowded onto asingle block. She clicked on one pushpin and up popped a picture, complete with dossier: Age, 67. ALevel 3 offender. Drives a red Ford Focus. Convicted of first-degree sexual abuse of an 11 year oldgirl.


Probably safer than giving it in person, said Ms. Ahearn, 44, a tough-talking smoker andworkaholic who started the group as a grass-roots crusade with several volunteers and now has 25part- and full-time employees and a million-dollar annual budget. Sex offenders may be good atwhat they do, but all of us are getting better at what we do.


Senator Charles E. Schumer and Representatives Timothy H. Bishop, Pete King and Carolyn McCarthyall joined Ms. Ahearn in her inconspicuous office in a strip mall here to announce the federalgrant. The group plans to use the money to compile sex offender data from all 50 states into mapson a revamped version of parentsformeganslaw.com, its Web site, scheduled to make its debut on May1; to create a national e-mail notification program to alert people about offenders in their ZIPcode; and to establish a toll-free number that Ms. Ahearn says will be the first national Megan'sLaw help line.


Critics call Ms. Ahearn's zealous pursuit of sex offenders counterproductive andunconstitutional, and contend that overexposure can deter the offenders from checking in with theauthorities.


Mapping out sex offenders makes them greater social lepers than they already are, said SethMuraskin, executive director of the Suffolk County chapter of the New York Civil Liberties Union.You're fostering punishment, not rehabilitation, and you're leaving them very vulnerable to mobjustice. You're basically challenging vigilantes to come to their doors.


Notification has also caused some complications. In Southbury, Conn., neighbors recentlypetitioned the local authorities to reduce their property tax assessments, claiming that aregistered sex offender's recent move into the area had brought down the value of their homes.


But Ms. Ahearn is constantly pushing for more restrictive laws against sex offenders on local,state and federal levels. She worked with lawmakers on state legislation limiting online activitiesof sex offenders, and on the federal Adam Walsh Child Protection and Safety Act of 2006.


She supports state legislation that would require real estate brokers to provide house hunterswith sex offender registry material, as well as a proposed Suffolk County regulation againstrenting to more than one sex offender per residence. She opposes, however, a proposal to prohibitregistered sex offenders from residing within a quarter-mile of homes for the elderly, worryingthat it could be used to overturn existing residency requirements prohibiting sex offenders fromliving near schools, parks and day care centers.


After Ms. Ahearn fought to keep paroled sex offenders out of homeless shelters, Suffolk Countyin 2006 began placing them in a trailer it promised to move from location to location to avoidoverburdening any one area; lately officials have been keeping the trailer next to the county jailin Riverhead.


Long Island has had its share of nationally covered sex crimes - from the Friedmans of GreatNeck, whose strange tale was documented in the film Capturing the Friedmans, to the Katie Beersdungeon case - and Ms. Ahearn has harnessed the issue to attain national prominence.


She is on a first-name basis with elected officials and has gained folk-hero status in manyneighborhoods dense with sex offenders.


Ms. Ahearn, a mother of two, was studying to become a social worker when New York State enactedMegan's Law in 1995, and she found that it was difficult, despite the new disclosure requirements,to get the names and addresses of local sex offenders from the authorities. So she began pressuringpoliticians and the police, all the while compiling her own local registry and posting it online,complete with offenders' addresses and graphic details about their crimes.


Publicizing such details has provoked anger among those on Ms. Ahearn's registry, and afternumerous threatening phone calls, she moved her office out of her home in 2000. At the strip mall,one room holds a mock witness stand and stenography machine that are used to familiarize childrenwith the setting before they testify in court. Ms. Ahearn's office walls are lined with photographsof politicians and notorious sex offenders, and drawings by victimized children.


On Tuesday, workers were cross-checking registry information and preparing updates for schooldistricts and community groups, based on the latest state data and notifications mailed from dozensof local police departments, a vital source of information on Level 1 offenders.


Early on, volunteers would gather information by visiting local police departments andhand-copying details to type later into the database. The group distributed the information toschools and community groups by mail or in person. Though much of the latest information is nowcomputerized, the group still has a huge number of files in binders, labeled by ZIP code, by lastname and by offender level.


These people navigate under the radar screen, Ms. Ahearn said of the offenders. We want themto know they're being watched.

(Stony Brook, New York)