I know who the Next Killer is.
I've been searching everywhere for clues of who the next killer might be and I've found the answer. Ever since not_queen said that "The answer is out there, have a closer look." I started my search. And after awhile, I found the next killer is: The Teacher.
At first, I, like many other people, thought there was a hint in the quote. After a lot of searching I found nothing. But while reading further into the comments, one comment stood out. I can't find the thread so I can't give credit where credit's due. But some mentioned that the Teacher might be the next killer because his files have been on the game files since August 2016. At first I laughed because I thought they were referencing Baldi from Baldi's Basics in Learning and Education. So I shrugged it off. The next day, I realized what they meant and looked up the Teacher. It lead to the Teacher's DBD wiki page. If you click on their power, Detention, it leads you to the rest of the killer's powers web page and the Teacher's power after the Clown's Power. THE TEACHER'S POWER WASN'T THERE BEFORE. And it's design looks like the rest of the killer's powers. Here's the link to the Teacher on the DBD wiki but you can also just look him up on the DBD wiki: https://deadbydaylight.gamepedia.com/Teacher. The Devs have worked off of previous things they've work on in the past before. I'd believe they'd do it again.
Other clues that lead me to the Teacher are the most recent cosmetics that came out for the survivors. Isn't it weird how Claudette just received a school girl outfit? I wouldn't put it past Dead by Daylight to reference the next killer by sending out a school outfit. Plus, not-queen said "Have a closer look." What I believe she was referring to was Claudette's new outfit. AND Nea's outfit looks like something you would wear to a Prep school. Much like Claudette's outfit. Feng's outfit I have a theory on. Her outfit reference's science/sci-fi. Now when not_queen said "the answer is out there." she must've have meant extraterrestrial out there. Which leads me to believe the Teacher is a science teacher.
Now if the next killer is the Teacher, that leads us to what his power might be. Detention sounds like a handicap or a punishing ability. Here are some possibilities on what this ability might do.
1. The ability is applied much like the Pig or Freddy and either disables one of the survivor's abilities or disables other survivors from being able to interact with the Detention-ed survivor.
2. Sends the survivor immediately to a hook much like in the Dev's recent game, Deathgarden.
3. If the survivor finishes a trapped generator, they receive Detention and receive a handicap.
They're could be many possibilities. Heck, it might not even be Detention, the Devs might have even made a different power for him/her.
Well I've laid all the facts on the table. I've searched and found an answer. Do you believe me?
Edit: Found the people who lead me to the Teacher idea, so shout out to Iceman and CakeDuty.