I have another theory I would like to throw out here.
I have had a real problem with the 2 loads of clothes she manage to wash. The picture of Travis in the shower where he is looking straight ahead is taken around 5:30. If I remember correctly, the roommate came back to the house at around 6:30. That leaves one hour to commit this murder, take him to the shower, wash him off (maybe her too), throw water everywhere, clean up as much as she could, gather all the weapons, remove any trace of her being there, load her car and wash the 2 loads of clothes.
I am thinking maybe she actually left and Travis stripped the bedding and put it all into the washing machine. There was only a few items in the washer that the police found and the forensic lady said she thought bleach had been used even though she couldn't say with certainty. There was no signs of bleach on the bedding found in the dryer. With so few items found in the washer, are you really going to take the time to wash 2 loads when you could have just put everthing into one?
I think she left, came back when he was in the shower, started taking pictures of him without his knowledge until the last one and then it went down hill from there.