Giving that interview and saying he shot the man was one of the most foolish things he could have done. If he made no statement or the like, he could have had a trial that was a circus in the court of public opinion.
As it was, he himself said that he killed the man. Given he was 48, he was basically looking at spending most of the rest of his life in prison, and with the Feds coming for him, he wasn't going to be able to rely on complicit local law enforcement to get off with a slap on the wrist.
From other reports I've seen, though not seen confirmation for yet, he emptied a rifle magazine at the feds when they came for him, didn't score any hits before they killed him with return fire.