RG didn't say anything about that in the skype call. I know that much, but he also said she was full dressed....so....I don't think it's impossible that he covered her, but I also don't think that it's impossible that someone like Rs, AK, or even FR discovered the body, covered her, and locked the door. The thing is, the leaving the door wide open part just doesn't seem to match any of the roommate's behavior.
I would think if FR happened to come by there and discover it, she would have made sure the door was locked because her computer was in there. Also, I think AK would have locked the door for a similiar reason. I just don't think either of the homeowners would have left the door wide open all night. Unless, of course AK was lying about that. If you're staging a break-in and (as other people theorize) you break the worst window, then I'm not gonna take the leap that you are cunning enough to think leaving the door wide open makes the burlgarly more believable. As some have said asked why RG didn't go back out the window, I'd think a stager might assume the "burglar" would go back out of the window. The only reason he wouldn't is if he were carrying something like a TV or couldn't see to get back down. Anyways, I don't think a stager would be thinking about that and thus leave the door wide open or lie that the door was wide open. They'd just assume the police would believe the burglar entered and exited from the same point.
So since I think that and don't think AK or FR would have been careless in locking up the house and keeping Mk's resting place from being disturbed, I have to believe one or two things, AK lied about the door being wide open or AK and RS weren't there.
RG on the other hand, did not know about the trick door. So I can see him closing it, but it coming back open. The police did the same thing. I saw a picture of the door with the gate closed and police tape on it, but behind the gate, the door had come open.