Emails reveal that U.S. Immigration and Customs Enforcement (ICE) pushed local law enforcement to scan the license plates of gun show attendees in southern California.

The emails date back to 2010 and were obtained by the Wall Street Journal (WSJ).

According to WSJ, “[ICE] crafted a plan in 2010 to use license-plate readers—devices that record the plate numbers of all passing cars—at gun shows in Southern California, including one in Del Mar.” ICE then “compared that information to cars that crossed the border, hoping to find gun smugglers, according to the documents and interviews with law-enforcement officials with knowledge of the operation.”

ICE faced push-back over the scans from privacy advocates.

ACLU attorney Jay Stanley pointed to license plate readers as an example that “highlights the problem with mass collection of data.” Stanley suggested ICE has taken two legal behaviors—buying a gun, crossing a border—combined them and used that combination to make people look “inherently suspicious.”

Gun Owners of America’s Erich Pratt went further, saying, “Information on law-abiding gun owners ends up getting recorded, stored, and registered, which is a violation of the 1986 Firearm Owners Protection Act and of the Second Amendment.”

ICE defended their actions as “an important and legal tool for pursuing dangerous, hard-to-track illegal activity.” At the same time, no arrests have been cited as resulting from the use of license plate readers on gun show attendees.

However, John Chicgos—CEO of the company that makes the license plate readers—believes using them to target gun show attendees is “an abuse of the technology.”

AWR Hawkins is the Second Amendment columnist for Breitbart News and political analyst for Armed American Radio. Follow him on Twitter: @AWRHawkins. Reach him directly at awrhawkins@breitbart.com.