This feels to me like a person with some sort of mental illness or breakdown and delusions of grandeur and persecution. Their explanation doesn't make much sense. If I were Daniel, I wouldn't respond any further.
Yeah, I agree. In his place, I either would have done nothing, or, maybe made a police report (not that I'd expect the police to actually do anything at this stage). Generally speaking, the less you antagonize someone whose first exchange with you is "I will slaughter you," the better, IMO.