At first I thought the stabbing came first , but now, after reading other people's posts, I am not as sure as I first was. But think about it. Why would she steal a gun if she didn't plan to shoot him? She was meticulous in her plan to kill him, making sure no one could place her in Mesa or even in Arizona. By taking the gas cans full of gas, making sure she didn't have to gas up in Arizona, this took some well-thought out planning. Why would she risk having all that bloody mess from 29 stab wounds and slicing his throat if something didn't go horribly wrong with her plan?
I don't know if the ME is right in his assessment that the gunshot wound would have rendered TA incapacitated. The reason I think this is that I personally knew a man who shot himself in the mouth with a shotgun, ripping off one side of his face and blowing out most of his teeth, but he still made his way out of his bedroom and called 911 himself, giving them directions to his home, made his way out the front door and was sitting on the doorsteps bleeding profusely when the EMTs arrived. This would have taken 15 to 20 minutes, and he didn't die from this horrible wound. So TA could have very well not been incapacitated if she shot him first if the bullet didn't go through the brain.
In the picture of TA's face, he looks to me like he is in total disbelief. it could have been that JA was standing there with a gun or a knife, either one. So I just am not sure which one came first, the stabbing or the gunshot, and I guess we will never know unless JA decides to tell the truth, which is very doubtful.