BOSTON (AP) _ A police officer stops you on the street, then taps something into a device in the palm of his hand.
The next minute, he knows who your relatives are, who lives in your house, who your neighbors are, the kind of car you drive or boat you own, whether you've been sued and various other tidbits about your life.
Science fiction? Hardly.
A growing number of police departments now have instant access via handheld wireless devices to vast commercial databases that contain details on just about anyone officers encounter on the beat.
In a time of terrorism worries, the information could theoretically save lives, or produce clues that an eagle-eyed cop could use to solve a case.
But placing a commercial database full of personal details at an officer's fingertips also raises troubling questions for electronic privacy activists.
``If the police went around keeping files on who you lived with and who your roommates were, I think people would be outraged,'' said Jay Stanley, a spokesman for the American Civil Liberties Union, ``And yet in this case, they're not doing it, but they're plugging into a company that is able to do it easily.''
In recent years, police departments have been testing different handheld wireless devices. Typically, they've used the devices to gain access to law enforcement databases meant only for police that, for example, alert them when someone is wanted for arrest.
At the same time, many police departments have been using desktop computers to search commercial databases to help them learn more detailed information about people they are investigating. These databases can hold billions of public records from a variety of sources. Thousands of law enforcement bodies now use them; five states have linked their own records with a huge commercial database in a federally funded program known as Matrix.
Now, in a convergence of the two trends, police are beginning to access the commercial databases using handheld wireless devices.
LocatePLUS Holdings Corp., a Beverly, Mass.-based company that says it maintains more than 6 billion records and has data on 98 percent of the U.S. population, announced this week that it would provide Blackberry wireless devices to state police at Logan International Airport. Two of the planes hijacked on Sept. 11, 2001, took off from Logan.
The officers can use the Blackberrys to access the LocatePlus database wherever and whenever they want, though the records don't include state and federal criminal justice databases or terrorist watch lists.
Such empowerment gains even more heft with Monday's ruling by a sharply divided Supreme Court that people who refuse to give their names to police can be arrested, even if they've done nothing wrong.
Justice John Paul Stevens, one of the dissenters, expressed concern that, with simply a name, officers could quickly tap into databases and learn a ``broad array of information about the person.''
Indeed, that's already happening.
LocatePlus now has more than 50 law enforcement agency customers that use wireless handhelds to access its database, said chief executive Jon Latorella.
Latorella said the company's database takes information from such sources as registries of motor vehicles, credit bureaus, property tax departments, telephone directories _ even unlisted numbers _ and courts to create computerized dossiers on people on demand.
ChoicePoint Inc., based in Alpharetta, Ga., also offers police wireless access to its vast databases, but so far has a smaller number of clients, said James E. Lee, the company's chief marketing officer.
Massachusetts State Police Lt. Thomas Coffey, who works at Logan, said he felt the LocatePLUS service would be useful.
``We're in the information business, obtaining information about individuals or groups. It's an intelligence gathering tool. It just allows us to do our job better,'' he said.
Privacy activists argue, however, that information collected for one purpose shouldn't be used for others. They call for federal standards on the access and use of data as well as mechanisms to prevent abuse.
The ACLU's Stanley said the need for standards is even more urgent as cops on the street get wireless access to databases, and could make snap judgments based on incorrect data.
Harlin McEwen, a former police chief who chairs the technology committee of the International Association of Chiefs of Police, said private database searching via handhelds is getting a lot of interest from police chiefs.
But he also cautioned that police should be wary about relying on information from databases not controlled and maintained by the government.
``It may be a tool for me. It may be a tip. But I'd better not rely on its accuracy without doing further investigation,'' McEwen said.
Privacy activists agree on the accuracy issue, and have broader concerns.
``These new services ... literally alter the balance of power between the individual and the state,'' giving the government more power, said Chris Hoofnagle, associate director of the Electronic Privacy Information Center in Washington. ``The private sector has become Big Brother's little helper.''