Charlie, when I listened to that 17 1/2 min tape from On The Record this week, I did hear Greta say that the Friday after they had found Michelle, a cop did talk to JY who simply told them he was out of town. And, It was actually Saturday, the wee hours of, when they confiscated the car - 4 hours after that Friday. Do you think that's what Greta was talking about?
Maybe Greta was wrong about the Friday. It was the following Friday after the funeral that JY was back in town and went to the cemetary.
Anyway, that is one thing JY did communicate to an officer very shortly after the crime was discovered.