If you pick up the phone and it’s a telemarketer, and you tell them, “Stop calling me and put me on the Do Not Call list”, then someone asks you if you “know” that telemarketer, you would say, “Yes, I know that jerk. They called me once and I told them to stop.”?
Because once Barwicki talked to Roger and asked him to stop, then Barwicki would "know" Roger. And then when Barwicki was LATER asked, "do you know Roger", instead of saying "no", he would have said, "yeah, I know that SOB. I called him once to ask him to stop". But that's not what he said. He said "no, I don't know him".
I don’t know, but that just doesn’t sit right with me.