Don't forget the Emerson case and federal law -- a restraining order can make it illegal to possess ammunition or firearms. Emerson was not convicted of a crime and the District Judge said Emerson had made no threat against his wife (he did threaten to the wife to harm her lover, but that is not included in the fed law.) [ U.S. Code title 18, section 922(g)]
They killed him, but they couldn't get his land. They didn't know that he had a tape recorder on his phone, so when they called in to tidy things up, his wife had a record of it. But, he was still dead.