I don't think it would be the son but if they really wanted to throw me for a loop then maybe he could be...
My very first impression when the episode ended was that it would turn out to be Milander's son. I just got the feeling that it might be him mainly because here he was being accused of a different murder, they let him go as he wasn't guilty, then to top it off Sara befriends him (somewhat) & takes him home. I could see on down the road them finding out he was the killer & then pull the "oh shit we had him the whole time" when it's all said & done.
No, he has no medical background, but is it for sure that the killer HAS to have a medical degree? The other thing that stuck out to me was the hand stuff -- Ray couldn't tie the intestine bow, but in the Milander-son side of the story the son's hand was "messed up" (sorry, can't remember exactly what they said about it), so it just immediatly made me wonder that because his hand was not like the average person, that maybe it's what allowed him to tie the bow.
Normally I don't speculate much with Vegas, I'm just the average viewer, so I could be wayyy off, but the son being "Dr.Jekyll" was my first impression. *shrug*
I'll just point out also that if it
is Milander's son, then the other CSI's were right in having bad vibes about him, & well, Ray was wrong.