... I'd agree that the 'don't remember anything' line is many times a sign of guilt. But then in this case the police know he was partaking in intoxicants, was punched because it's on tape, has a roommate that is alibiing him, and has another person (JR) that moves LS forward in the timeline and away from CR (which if to be believed means whether you believe CR's blackout or amnesia (whatever word you want to use) claim is true or not also means it doesn't matter because JR's statement has removed opportunity from CR's night).
If JR is lying then it leaves the sticky detail of figuring out why he'd lie and make himself an accessory to a crime if CR is the guilty party. Let alone why MB would as well.
....Unless they are all lying and all involved. But then that leaves another question- Why in the world would they allow CR to claim memory loss, amnesia, blackout, or whatever while they have to maintain a more coherent story. And one that must check out enough not to trip themselves up? Of course it's possible they decided that was their best option to minimize inconsistencies.
Unless whatever happened happened after CR went to bed and it's MB and/or JR who actually need the cover story.
Lots of possibilities but none of them line up perfectly without some holes. That's why I think people are starting to reach somewhat to fill those holes.
