Audio problem: When Karen is in the house talking on the phone, she says "He won't come down," (referring to Toshio) but her lips don't move.
Audio problem: After the detective listens to the message that Susan leaves for her brother on the answering machine, the detective pushes the button to locate the missing phone. The detective as well as another officer begin to follow the sound of the ringing phone which is very loud and audible near them. As they begin walking down the hallway towards the door the ringing becomes muffled and when he opens the door it becomes loud again.
Answer: Kayako was murdered by her husband when he found out that she has romantic feelings for another man, since this would be a crime of passion driven by hatred the cutting out her face from all the photos then sinisterly pinning them to the door is another sign of his hatred. Like him removing her from the family and cause futher pain with the needles. Also to display her face would most likely be a way of shaming her further, insult to injury and all that.