10:15 a.m. EDT July 28, 2014   In a crime-fighting tactic that sets civil libertarians' teeth on edge, police in Monroe County and other urban counties across New York state are collecting and archiving tens of millions of records that track vehicle movement.

The records are stored in a series of loosely connected secure computer servers, accessible directly or indirectly by police from one end of New York to the other and by federal Homeland Security officials. Each of the records, which are gathered by license plate cameras mounted on police cars or at fixed locations, includes a photograph and the time and place that a particular vehicle was imaged. Strung together, the records can paint a picture of where a person has traveled — whether to the scene of a crime, a doctor's office or to church.

The system can instantly alert patrol officers of a "hit" on a stolen car or, more often, a vehicle whose registration has lapsed and is ripe for ticketing. Stored records also can be accessed later as part of criminal investigations.

Records used for those purposes, though, constitute only a small fraction of all the data being saved. The vast majority of the vehicles tracked in the license-plate data were driven not by scofflaws or criminals but by innocent citizens who happen to be photographed driving to work or while running errands.

And least nine of New York's most populous counties — Monroe, Erie, Onondaga, Albany, Broome, Westchester, Suffolk and Nassau — are now engaged in long-term storage of these records.

The purpose is to allow investigators to go back in time and track where a criminal suspect spent his time or look for witnesses who might have been driving near the scene of a crime. Not knowing which records might be useful, authorities are choosing to keep them all.

In Monroe, Albany and Westchester counties, as well as in New York City, the policy is to keep all license-plate records accessible for five years. The New York State Police also retain records for five years. Erie and Onondaga counties plan to keep them for a year.

At least some of the records will be kept indefinitely beyond those designated periods, available with approval from a judge or district attorney.

Advocates of license-plate readers say stored data helps investigators who need to hunt for evidence of criminal patterns or associations.

"There are privacy concerns and there are legitimate public safety concerns. In every occasion it's important to look at those and find a balance," said Michael Green, executive deputy director of the state Division of Criminal Justice Services, which has paid for equipment to store the records and encourages its use. "If you look at the public safety side, they are another tool that have allowed them to solve significant cases — murders, rapes."

How often use of these records help solve crimes after the fact is not clear. Several police officials told the Democrat and Chronicle they don't keep track.

Kaelyn Rich, director of the Genesee Valley chapter of the New York Civil Liberties Union, said long-term police storage of information about vehicular movement makes it "a tool for mass surveillance and mass location tracking.

"It can be a reasonably useful technology. The problem is they're storing records that are not hits. They're keeping these millions of other records on everyday people going about their business," Rich said. "In the United States, it's a core principle that the government does not invade people's privacy and they do not collect information on people in case they do something wrong."

New York law is silent on license-plate readers and record retention.