An Chicago-area gun dealer was sentenced to four years in prison for selling nearly a dozen guns to people he understood to be prohibited buyers, the U.S. Attorney’s Office announced last week.

Patrick Keiran, 41, was sentenced in a Chicago federal court on Oct. 14 for selling 11 guns to buyers, a convicted felons and an undercover federal agents posing as felons, in 2014. In both instances, he doctored paperwork to finalize the sale by using names of other customers.

“[Keiran] let these individuals walk out of his store with brand new firearms and no possible paper trail for law enforcement to follow if those guns were ever used for criminal purposes,” said Assistant U.S. Attorney Christopher Parente in press materials.

Keiran was issued a federal firearms license in 2013 and operated American’s Choice Firearms and Ammo in Gardner, located about 70 southwest of Chicago. He was arrested in July 2014 and his gun store was closed.

According to the criminal complaint, agents with the Bureau of Alcohol Tobacco Firearms and Explosives received information from a confidential source in May 2014 that Keiran was selling guns to prohibited persons and falsifying ATF paperwork to fraudulently legitimize the sales.

Shortly after receiving the tip, on May 27, 2014, two undercover ATF agents and the informant met with Keiran at a bar in a nearby town. At one point during the meeting, one of the undercover agents stepped outside with Keiran in an alleyway to discuss a possible sale. The undercover agent told Keiran that he would not be able to pass a background check to which Keiran responded by saying it would not be a problem.

Keiran provided the undercover agent a business card and told him to call him before heading over to his gun shop so he could turn off the surveillance cameras.

The next day the undercover agent arranged a meeting with Keiran. On May 29, 2014, Keiran sold the undercover agent three 9mm handguns for $960 and used three different names for required ATF forms. Keiran also provided three different valid Firearm Owner Identification Card numbers (a FOID is required to buy and own a gun in Illinois).

There were four other transactions between Keiran and undercover agents posing as prohibited buyers throughout June 2014 in which eight other guns, including handguns and rifles, were sold.

Keiran pleaded guilty to one count of selling a firearm to a prohibited person in April. After his 48-month prison sentenced, he’ll have three years of supervised release.