I think MM knew that JC was leaving, she saw the writing on the wall. She was mad, she phoned her parents numerous times, they realised that she was border-lining flipping out and jumped in their car to drive up. I believe that the arrival of TM & SM was a bit of a surprise to JC that day but took it in his stride. TM & SM had numerous conversations with MM that evening to try to calm the situation, all the while putting the blame on JC as him not being good enough for MM.
JC went off to bed for a peace while MM stayed up with her parents for a while, they eventually went to bed but MM, being agitated, was not able to sleep and started pacing around the property. She comes across the paver while she was pacing, the paver was in a pile by the back door which would be just outside where her parents were sleeping. She was mad with rage, realising that he was leaving and taking the children, the conversations that she had had earlier that night with her parents had dashed any hope, effectively they dismissed any fantasy she had. But during these conversations, I believe that they both placated her in a way they have always done, she was the little princess, he was the nasty Irish man, she was better than him. Making her feel important had worked with them in the past but a totally wrong tactic to take in this scenario. The conversations had got around to the domestic violence issues and the false case that she had been trying to establish. She knew that she did not have a leg to stand on and her parents would have confirmed this. She would have been bubbling up with anger inside. I believe she grabbed the brick and charged up to the room, found JC in bed and attacked him. I believe that, from that point at the least, it was all intentional.
She was a strong girl and with all that adrenalin, she would have been a force to be reckoned with, particular if you are being caught by surprise in your sleep. JC got out of bed, staggered and made his way to the bathroom, MM then goes to the garage, which is on the same level as their bedroom, grabs the baseball bat and further attacks JC as he emerges from the bathroom. At this point, I think that TM came up from the basement to a horrifying scene. SM also came up, they started assessing the scene and calming down. TM knew that he had to pick one, save JC or save MM. He choose wrong. He instructed SM to go back to bed, she could not be involved, hard enough two people sticking to a lie, but three. In the story they concocted, TM had to have some element of truth so he hit JC with the bat. Once he did this, he was up to it to his neck. This all happened well over an hour before they phoned 911.
TM thought, foolishly and arrogantly, that he was going to pull the wool over the eyes of local law enforcement. He lost, and he and the rest of his family will pay the price for the rest of their lives for his foolishness and arrogance.
