What little I know offhand. Travis' room is on the other side of the large home. The roommate noticed a faint smell when he came home the day before but didn't think much of it, was very faint. The one roommate basically just sleeps there. It isn't unusual for them to see each others cars there and to not be home because of travel and or using other transportation.
I know. I'm not saying they're lying or had anything to do with this. Just saying is that their story is not totally credible with a car in the driveway, an untended dog, no requests or instructions and a funk that most likely would have been present more than a little. I have house with similar square footage and a split floorplan. In AZ in June it's in the 90's or 100's every day. So either the ac was cranked non-stop or it was hot and stank. Chances are you would have whiffed it unless you had a separate entrance. Maybe they did, idk.