Laura/Erica... was hinted at as strong suspect in the last episode. Her brother is most likely the set photographer who told Ray about the wild parties. This is actually what I don't care about... The killer/killers is both after thoughts, as well as many of the maze of people who were a part of Catalyst.. (in some form).... I just think there wasn't any development for most of these characters, they barely got any screen time. The fallout after is the most interesting story. This is I why I think there is a big schism in the show... I think Pizzalato is trying to be too clever, ultimately being forced to tie loose ends..... rule number one in Visual Writing/Filmmaking... "Show it, don't say it."
I do enjoy the quirkiness of the show... and I think the different directors (there has been multiple this season) have done a good job of conveying that the characters are trapped in hell... the colors of fire has been a consistent theme. The score during the Orgy scene was right out of a 70's noir movie... DePalma esque....
Last season Cary Fukunaga, the director of the entire first season, seized a level of control that Pizzalato wasn't happy about. Fukunaga is a film director, in motion pictures the director has the most creative control (vs tv). Pizzalato, as the show runner & the writer did not invite Fukunega back, and it shows in the work.