"He may have been law-abiding, up until he tried to interfere with the arrest of a violent illegal alien. At that point, he was in violation of 18 USC §111 - penalizes one who “forcibly assaults, resists, opposes, impedes, intimidates, or interferes with" immigration officers. Penalty 1 to 8 to 20 years. Actively stepping in to interfere with the arrest, with or without a gun, probably put him in the 20-year category. If the officers felt threatened with their lives, that was far over the line. Even just creating a distraction puts officers in danger. There were probably several other laws violated."