Salt Lake County sheriff's officers want residents to inform them of suspicious neighbors.

"Do you know someone who has strange visitors at unusual hours at home or business?" asked a newspaper ad. Or who has "given suspicious stories about sources of income or jobs"?The ad urges readers to "do your part" by calling a recorded tip line to pass on information about their neighbors.

Deputies say they're trying to identify the kingpins of large criminal organizations who may be living like normal Americans.

Some law-enforcement experts say the ad encourages neighbors to spy on one another and could poison a neighborhood with mistrust and paranoia.

"The cost of reduced trust in neighbors is just not worth it," said David Kopel of the Denver-based Independence Institute, which studies criminal-justice issues. "It leaves the community worse than before. We're burning down our village in order to save it."

Sheriff's Lt. Dale Bullock sees it as a way to strengthen Salt Lake County's neighborhoods through "community-oriented policing," which puts emphasis on citizen involvement.

"Neighbors will pull together when there's a problem in the neighborhood," he said. "We're targeting the top of the pyramid, the high echelon of the criminal enterprises. We gave this a lot of thought before we did it. . . . We didn't view it as a George Orwell 1984 issue."

The ad has generated several complaints from residents who view the request as too intrusive, Bullock said. But it also has given investigators at least five useful tips about possible drug dealers, which will be investigated.

Police will use financial records, surveillance and other methods to determine if the residents' incomes are legitimate, Bullock said.

A similar program has been tried in Milford, Conn., where police took out a display ad in a local newspaper. The ad included a cutout coupon for concerned residents to mail in tips about suspected drug houses on their block. Despite complaints from civil-liberties groups, Milford police said the program generated more than 150 search warrants and 200 arrests.

Such tactics can generate bogus "leads" when information comes from someone who may hold a grudge against a neighbor, said Eric Sterling of the Washington-based Criminal Justice Policy Foundation. It is also conceivable that residents could use the tip line to harass ethnic minorities who move into a new neighborhood, he said.

This wastes valuable police time and can make an innocent taxpayer the target of an unwanted investigation, said Kopel.

"Suppose some guy moves into a neighborhood and he's a security guard and he has irregular work hours and he has a bunch of funny-looking friends from college," he said. "Do we want to live in a society where that guy has to worry about a SWAT team coming through his front door?"

Bullock said the sheriff's office has an internal screening process that weeds out phony tips and protects honest citizens from scrutiny.