Bingo. The LEO should have just left.
I dont think the guy was being terribly rude. I can understand how frustrating it would be to have someone bug you, then not accept your answers. Chances are this wasnt the first time he has been asked about this guy too. My uncle used my grandparent's address as his legal address, even though he rarely stayed there. When he was out of prison, the police frequently waited on the road in front of their house for him, and several times asked my grandparents where he was, when he would be back, etc. He was not wanted, they just wanted to talk to him about this or that. After he was arrested again (this time in Michigan, not Indiana) the police would still occasionally show up for this or that and ask my grandparents questions, despite the fact that he was currently incarcerated. They told different officers this several times, but for the first few months would still occasionally have someone stop by.
Some people will put up with that and answer the questions every single time, others are going to get annoyed. Whether this was the first time, or whether this was the 100th time, the guy had every right to state he did not want to speak to the officer, and the officer had no real reason to arrest him, other than to try to intimidate him, which is an abuse of power, IMO.
