Maybe they found weapons in his house that he didn't have proper permitting for......
Anyway wait I Googled it. He had 5 charges brought against him that would have had him serving time even without the murder charge.
Per several articles......here are the laws he broke.
As explained by Ben Volin of the Boston Globe, the weapons charges against Hernandez carry a maximum sentence of 10 years for each of two counts of carrying a “large capacity firearm”; five years for one count of carrying a firearm without a license; two years for possession of a firearm without a Firearm Identification Card; and two years for possession of ammunition without a Firearm Identification Card.
@Ramhusker I think we probably disagree about firearms based on the "no freedom" zone remark you made. He had illegal weapons and ammo and that isn't "no freedom" it's breaking the law. This isn't jaywalking.