Two months ago, the Pittsburgh Police Bureau's North Side station acquired a new weapon -- a computer-based system that lets officers alert residents to crimes, missing persons and other emergencies almost instantaneously.

At its best, the system will allow residents just as quickly to report back to police any suspicious activity on their streets. At the least, a speedy tip from a resident could cut the amount of time police spend investigating.

It's too early to attribute any arrests to public participation, said Officer Forrest Hodges of the North Side station, "but it has a promising future."

Called CitizenObserver.com, it's a software program that provides two-way communication for police and their most helpful, watchful neighborhood collaborators. The system even includes anonymous tip forms.

The system was a gift from the Northside Leadership Conference, which raised $11,000 for a two-year use. The money came from seven banks, a TV station and the North Side's two councilwomen, Tonya Payne and Darlene Harris.

"We aren't allowed to raise money," said Officer Hodges, "so the conference was our angel."

The system allows the police to issue bulletins with several levels of discretion, from general alerts anyone can read to site specific, insider information meant for block-watch contacts. A separate level lets banks and other merchants get alerts specific to businesses.

There's no cost to residents to receive the alerts.

The city's other four police stations are clamoring for the system.

It is currently in 300 law enforcement agencies in 30 states, said Terry Halsch, president of the St. Paul, Minn.-based company. The North Side station is the company's first Pennsylvania client.

City Councilman Len Bodack convened a meeting of council members and police representatives Monday to discuss the possibilities of a citywide activation.

He said police commanders in District 7, which he represents, are lobbying him to get the system.

"It's a tool that stretches and enhances the efforts we're making with our block watches," he said. "I've directed our budget guy to converse with [city finance director] Scott Kunka on the mayor's end to see if we can find money already in our budget."

"All of council is looking for the full $44,000 so it can become citywide by the end of May," said Councilman Bill Peduto.

Police Chief Nate Harper said the system "could be rolled out throughout the city by late May or mid-June" with a variety of funding sources, as happened on the North Side.

"It's an excellent tool for communities and business districts throughout the city," he said. "What I hope is that it increases neighborhood block watches. That's a component I feel very strong on."

Officer Hodges said his 20 North Side block-watch groups have responded enthusiastically, but most of the feedback so far is about potential.

"Given that it hasn't been in effect long, we haven't gotten many alerts yet," said Kimberly Flaherty, coordinator of North Side Safe Streets.

"I got a credit card scam alert" last week, "and it made me feel a lot more comfortable that it was coming from Zone 1 [the North Side station], because you hear about these scams a lot and have to wonder whether it's real or urban legend."

Also, in the past, when burglary suspects were being sought, she said, "you had to post their pictures on telephone polls. But if you can see a photo instantaneously, who knows where it might lead? You can see the potential."

While civil liberties advocates have voiced concerns about the effects of overly vigilant and assertive anticrime neighborhood watches, this police tool has not become an issue.

"I don't have any alarm bells going off," said Vic Walczak, legal director of the American Civil Liberties Union in Pennsylvania.

Jean O'Neil, spokesman for the National Crime Prevention Council, said she has heard of the system but not seen data.

"Anything that gives the police a way to encourage reporting and give feedback to citizens is good," she said. "Block watches that are functioning well are an amazing resource."

The North Side system's cost of $11,000 over two years pales in comparison to the cost of crime.

Ms. O'Neil said a research institute extrapolated costs related to various crimes on behalf of the national council and determined that one robbery with injury, according to 2003 data, cost $26,700.

"That does not include the cost of investigating, apprehending or prosecuting," she said.

Mr. Halsch developed the system after a decade of selling training devices to military special forces and SWAT teams, he said. He started the company in August 2001.

To illustrate its possibilities, he told of one case solved by the system.

A man broke into a Green Bay, Wis., house and stole $300 worth of change from a giant piggy bank. An alert went out, and a few days later, when a man went to a bank to exchange a large load of change, a bank official remembered getting the alert, called police while the man was there, and the police arrived before the change was even counted.