The license plate readers requested for the political events “would detect any stolen vehicles attempting to enter the outer perimeter of the event and possibly allow for some record of attendees in the event that a serious (incident) occurred,” a state police sergeant wrote in a 2009 letter that outlined some of the department’s uses for the license plate reader technology. Up until a February legal opinion issued by Virginia Attorney General Ken Cuccinelli on the collection and dissemination of license plate reader data, state police beginning in 2010 had stored the images of roughly 8 million license plates — some for as long as three years — on a server in the department’s data center at state police headquarters in Chesterfield County, said state police Sgt. Robert Alessi, the department’s statewide coordinator for the program.The long-term data storage ended following Cuccinelli's opinion. Now, Virginia State Police say license plate data is dumped after 24 hours, unless a tag is being pursued as part of an ongoing investigation. The American Civil Liberties Union issued a report last month criticizing national police usage of license plate readers. Across the US, about three-quarters of law enforcement agencies use such devices, while 85 percent tell the ACLU they plan to increase their reliance on the tools. And much of the monitoring is paid for by the federal government. The ACLU report reads that in fiscal 2012, the Department of Homeland Security shelled out more than $50 million in grants to aid police agencies buy license plate readers. Back in Virginia, state police have 48 of the devices dispatched across the commonwealth, the Times-Dispatch reports. Most are affixed to highway patrol cars, but two of them are masked inside traffic barrels.