A New York City undercover investigation heralded as the first of its kind has found a "vast and largely unregulated market for illegal guns" on the Internet, and the worst offender is a website that has gotten mixed up with the law before: Craigslist.

In the report released Wednesday, entitled, "Point, Click, Fire: An Investigation of Illegal Online Gun Sales," investigators found that sellers on Craigslist agreed 82 percent of the time to sell guns to a purchaser who admitted they probably couldn't pass a background check. Not that anyone is supposed to be selling guns on Craigslist. The website, which depends on self-policing, claims to ban firearms sales yet thousands of guns were found listed for sale there, according to the report.