Hard to say since 100% of all TV is produced for entertainment and it of course gets biased towards the producers views. Footage gets edited out of order to make it seem more shocking than it is. Almost anything could have happened and the show just left out details. Hypothetically, he could easily have had an outstanding bench warrant for something simple like failure to appear in court, but the producers cut it to make it look like he was arrested for the gun. Now I'm not saying that's what happened but it easily could have.
Mike Rowe wrote a great little post on his awesome show, Dirty Jobs, how even they do things to make the show more exciting. While they don't script it, they will do something they know will probably cause hilarious failure because its good television. I am paraphrasing here but his parting comment was, "If there is one thing you NEVER see on TV, its reality."
To get the facts you would need to track down the events to where it actually happened but that's probably impossible. Do you remember what was on the screen when the Cop Killer Gun line was said? Often they will take long shots of items and then voice over additional material. Hollywood is brutal about ignoring reality.
My 2 cents