Wow, very detailed and very plausible.
I find it quite amusing, to read all the things RG was able to do, without any resistance of MK and no escaping of her; it sounds, that she must have been intoxicated during all these things: Forcing her to the ground, cutting the bra off with two hands, keeping her mouth shut, sexually assaulting her from behind, torturing and stabbing her etc.; and now he also grabbed a pillow during "his" attack.
Concerning the towel. Do you think he first stabbed the victim, then went away, grabbed a towel, returned back to the bleeding victim and then placed the towel on his trousers? Aside from the fact, that this theory is in itself implausible, it doesn`t explain, why the towel was so thoroughly blood-soaked. The towel can`t get soaked in blood to such a degree, if it`s kept away to some distance from the blood source and much less if the person, as it`s the case in your "theory", is eager not to get blood on his clothes.