In what appears to be a legal first, a Virginia man has sued the Fairfax County Police Department for collecting images of his license plate in a massive database.

Harrison Neal, a Fairfax resident, filed the suit after learning that his license plate had been scanned by an automatic license plate reader twice last year and stored in a police database, even though he was not a suspect in a criminal investigation. The American Civil Liberties Union of Virginia filed the lawsuit on Tuesday on behalf of Neal.

Although individuals have filed suits to obtain records stored in such databases, this is the first case known to target a law enforcement agency over an alleged illegal use of a database.

The database, the complaint (.pdf) asserts, violates a Virginia statute—the Government Data Collection and Dissemination Practices Act—which prohibits government agencies from collecting, storing, or disseminating the personal information of individuals unnecessarily.

Automatic license plate readers have become a hot topic in recent years, akin to the government's warrantless use of GPS trackers on vehicles and stingrays or IMSI catchers that are used to track the location of cell phones and other mobile devices.

A California man discovered that authorities had collected images of his two cars 112 times in a database, including one that showed him and his daughters in their driveway.

The readers, often mounted on a vehicle or in a fixed location, use cameras and optical character recognition technology to take images of license plates and store them in searchable databases. Insurance agencies and impounders use them to locate stolen vehicles or vehicles belonging to people who are behind on their payments. But law enforcement agencies also use them.

Civil liberties groups consider the readers and databases a violation of privacy because it's possible to discover a lot about a person simply by recording the location of their car over a period of time. The readers can also capture much more than license plates. In California, a computer security consultant named Michael Katz-Lacabe discovered that authorities in his San Francisco Bay Area town had collected images of his two cars 112 times in a database, including one image taken in 2009 that showed him and his two daughters exiting one of the cars while it was parked in their driveway.

But proponents of the technology argue that the data collected is innocuous compared to other data like cell-phone location information.

“We’re not insensitive to people’s right to privacy,” Terry Jungel, executive director of the Michigan Sheriffs’ Association said in 2013 over a battle in his state about license plate databases. “If Big Brother is going to abuse information, there’s better information to abuse than this."

Neal discovered images of his car in the database maintained by the Fairfax Police Department after filing a public records request recently. In response, he received two sheets of paper containing an image of his car, along with a chart indicating the times and dates the images were taken and a map showing a street location, believed to be the location of the reader when it snapped the images.

But Virginia's state law should have prevented his images from being stored. In February 2013, the state's attorney general issued an opinion advising the State Police that automatic license plate readers do collect personal information, as defined by the Act, and therefore agencies cannot legally collect and store that data unless it's related to a specific criminal investigation. The pronouncement came in part after it was discovered that Virginia State Police had used license plate readers in 2008 to collect information about people who had attended rallies for Sarah Palin and Barack Obama during the presidential election that year.

Subsequent to the attorney general's pronouncement, the Virginia State Police stopped storing license plate records and established a policy for purging such information within 24 hours after being collected by a reader, unless the information is relevant to a criminal investigation.

But, according to the ACLU of Virginia, other government agencies in the state have failed to follow suit. The Fairfax Police Department, for example, stores license plate images for up to a year, regardless of their relevance to an investigation.

The department also has an agreement with law enforcement agencies in Maryland and the District of Columbia to share information collected in its database.

“Like many other technologies, ALPRs have legitimate law enforcement uses,” Rebecca Glenberg, legal director of the ACLU of Virginia said in a statement. “We do not object to the real-time use of ALPRs to compare license plate numbers to a current ‘hot list’ of vehicles involved in current investigations. The danger to privacy comes when the government collects tens of thousands of license plate records so it can later find out where people were and when. The intrusion is magnified in the Washington, D.C. area, where multiple law enforcement agencies may access each other’s information.”