OK so, spoilers(?) ahead or at least theory time for me
as Ive replayed the game for Carlos, among the other routes, and so an so (although i noticed the oddity my first time around and as I'm playing it right now, I'm at the lunch scene with shay) the way the flow of info Ive been been getting, its hinting (at least for me) that Chris is the rapist, i have some points to this,first his attitude, it seems forced to me, then there's the moment Russel first appears in the lab, and Chris's persona changes, which weirded me out, then we get to the whole Russel dilemma, Russel doesn't seem to be trying to win us over, its more like hes just being kind, we even see this when he takes off his beanie to put Zach at ease, even though he makes multiple lewd suggestions, he does it in a joking way, hes never really serious about it times, and then we get to the part were shay is talking to Ben about how "Chris talks about him a lot." which gave me some red flags. and in general, i've never really liked Chris due to his personality (i.e it feeling forced) and i trust Russel more due to him being the first person we meet outside of Santa Lucia
sorry for how long this is