There's one thing that doesn't make sense so far - Why the "killer" is killing only white girls? It's clear he see them as traitors to their race(even if it's not sure the killer is really white guy/girl or just pretend to be on purpose) because they let themselves have fun with black guys,but then why killing only the girls and don't do anything to the guys he seem to hate?
1st theory is that may be the killer is actually a black girl pretending to MC to be one of his race(after all the killer is always masked and probably using a device for making his voice different) so that way she can take revenge of all white girls for fucking black guys,probably thinking that the black guys now only want white girls and dont give attention to the black girls anymore(may be hers parents divorced because hers father cheated on hers mother with a white girl and after leaving them alone for the white girl at some point she lost hers mother that wasn't able to take that fact and that's how she become so evil and for years planed hers revenge of the white girls) because of which she start killing the white girls that fucks with black guys and that's why she spare the guys,because they are one of her own race - this will make a big logic!
2nd theory is that the killer is in some kind of agreement with some of the most powerful black gangster guys that let him kill the white girls he wants but he can't do anything to the black guys and that's why they are not killed too and he probaly need to make it up for them loosing a good whore/slut they can always enjoy!
3rd theory - the killer if he is once again really a white guy is probably a real insane psychopath who only want revenge (probaly because of something in the past that did turn him into such a psychopath)and don't even realize that if he keeps killing white girl after white girl just because they fuck with black guys,at some point(even if took a while) there will no longer exist any white people since there will no have any more white girls to give birth to him or the rest of white guys and if there's no any white girl to give a birth to white babys his own race will stop exist and there will be only the race he hates,the black race,even if white guys mix with black womans the black color is more dominant and will once again give birth to black or brown baby instead white one. Here's another question coming too - why there are no any black girls(may be the only black girl there is the black teacher's wife) since obviously there is a lot of black guys - who did give birth to them? are they all single kids and don't have sisters or any other family or relatives? didn't any of them ever married or dated a black girl and only go for the white ones? and if there are black girls and they also mixed with white guys like the white girls are mixing with black guys,then why the killer don't also kills the black girls or the white guys because of that too? There's too many questions about all of that how it happens that the killer is only killing white girls and nobody else!
PS: I'm not sure but after the last time i start to think that may be the killer is the brother of the most hot and sexy girl in all that game - Savannah! We never see him till that story from the past where he seems to not be a party guy,more cold,try to act as a father person to Savannah not letting her enjoy partying and instead when see her smoke weed and doing some naughty videos twerking hers butt for her social meadia acount he grabbed her and take her home threaten to tell all to their father; at that party when wallking near one of the rooms and see that Savannah's boyfriend is rapping hers so called best-friend and she see him and asked for help,he didn't do anything and just go away,not even telling that to his sister...he acted rude with Jammal when grabbed Savannah to take her home and before that was always isolated in another room alone not joining Savannah and hers friends when she decide to take him with her exactly of that,to have some fun and relax.... All that stuff are making me think that if the killer is really a white guy,it's probably Savannah's brother but guess will need to wait a lot longer before finally find who it is and how he become the killer!
PS2: IF it happens that the killer is not a white guy but is a black guy whose sick plan was to humiliate even a lot more the MC trying to turn him into the killer of his own race while meanwhile till that happens he did kill all white girls(may be even fucked them before putting his mask and go to kidnap and kill them after that) who fucked with black guys,trying MC see his point and start to believe he is right,then probably the one who can be such a sick and insane psycopath from the black guys so far is probably Jamal or his best friend who tried to betray him! But i don't really think the killer is a black guy,more like is a black girl then black guy and that's only if i'm right about my 1st theory and the killer is not really a white guy/girl !