MANSFIELD - Has the neighbor next door recently built a room over his garage, or installed a new swimming pool?

Is it possible that neighbor did not tell the town that the value of his home has now increased - and thus, so should his tax bill?

Well, now you can do it for him.

The town Web site has added a free database with information on every parcel of property in town. Anyone can go online and get property values and property cards, parcel plan numbers, maps, photographs, lists of abutters, zoning information, and more.

That information was always available at town hall. But, Town Manager John D'Agostino said, "Hopefully this will allow anybody who has access to the Internet to get the same information, rather than coming down to the assessors' office." And what D'Agostino really wants you to do is - well - rat out your neighbors.

"I urge all our residents to take a look at their neighbors' property, and if some of their neighbors have been working on their property, we would certainly like to know that," D'Agostino said.

Schadenfreude never tasted so sweet.

Selectman George Dentino accused D'Agostino of seeking to turn residents into "a police force for your assessors," and asked if the town manager had been "lobbied by the American Association of Real Estate Agents."

But D'Agostino dismissed the idea that he was trying to create Mansfield's own Stasi.

"We usually get a ton of calls when we make this announcement, who say, hey, I'm looking at my neighbor's property and it's valued more than mine," D'Agostino said.

"When we hear from neighbors, we go out and we take a look and we see and confirm as best we can whether or not the information is appropriate," he explained. "Some of it is stale and outdated."

D'Agostino added, "And if you want to call and update your property card, we'd be more than happy to take down that information, as well."

Selectmen Chairman Lou Amoruso pointed out that the database has other uses, as well.

"I think a lot of people want to know about their property," he said. "It's nice to be able to take a look at your property and see how you rate, compared to everyone else." To visit the Mansfield assessors' online database, visit www.mansfieldma.com/assessors/ and click the link that says "Click here for Assessors' Online Database and GIS Mapping."