He was issued a FOID Card (Firearm Owner ID) in Illinois back in 2014, and that approval was because they failed to find a felony conviction on his record.
When he went to apply for his concealed carry permit, however, that’s when they found the felony record in Mississippi. His permit was denied, and his FOID card was revoked.
But he still had a firearm. Illegally.
[the gunman] had six prior arrests by the Aurora police, including charges of domestic violence.
So let’s see where we are here. We have a convicted felon in illegal possession of a firearm. He must have lied about his record on his FOID application, which would have been another crime.
[the gunman] was able to purchase his gun legally thanks to an error by the Illinois State Police, who failed to find his felony conviction and issued the FOID card. And the Mississippi felony apparently didn’t show up on the NICS background check Martin underwent when he bought the handgun, either.
So [the gunman] was a criminal in illegal possession of a firearm, carrying a gun on his employer’s premises (which, no doubt, was also a gun-free zone).
via The Truth About Guns
What’s the takeaway?
Protect yourself by carrying a firearm. Criminals fall through the cracks, and they’re going to get firearms. There isn’t a damn thing that anyone can do to stop each and every single one of these lunatics. If there are one million gun laws on the books, these criminals will still find a way to kill. With guns. And if it’s not with guns, it’ll be with something else. So what can you personally do to help?
Carry a gun.