John Patrick Bedell, who shot and wounded two police officers near the Pentagon earlier this month, bought at least one of his 9 mm guns at a Nevada gun show, The Associated Press reported yesterday.

Law enforcement officials say Bedell, a man with a history of severe psychiatric problems, had been sent a letter by California authorities Jan. 10 telling him he was prohibited from buying a gun because of his mental history.

Less than three weeks later, Bedell bought a 9 mm Ruger at a Las Vegas gun show by exploiting one of the largest loopholes in the nation’s gun control laws: While federal law requires licensed gun dealers to perform background checks on all prospective gun buyers, unlicensed sellers — like those who often set up shop at roaming gun shows — are exempt. The background checks are designed to prevent sales to those legally ineligible to own guns, including felons, illegal immigrants and, like Bedell, the severely mentally ill.

Several bills floating around Congress would subject unlicensed vendors to the same background check rules as licensed sellers. Considering the political environment on Capitol Hill in recent years, however, even sponsors of those proposals concede that they’ve got no chance of passing anytime soon.