If this rumor is true, is it a possibility that MM used the excuse that her son was sick? Perhaps, she was feeling uncomfortable. And, is it a possibility that JY was really looking forward to seeing her and that he was so disappointed and upset that he took it out on MY? In his warped mind, he could have been thinking, "If I hadn't been married to you, she would have come to visit." He could have been so angered that he took it out on MY.
OJ Simpson murdered his wife the night that his girlfriend, Paula Barbiera (sp?) broke up with him. She left him a voicemail breaking up with him and flew to Las Vegas to be with Michael Bolton, I believe. I think this event, coupled with Nicole snubbing him, caused him to viciously murder her.