My thoughts

It’s definitely her brother!!! It has to be!! First of all auburn hair, search it up folks ITS NOT BLONDE. TBH it doesn’t help with the fact that the blonde guy has the car of the suspect but other than that the fact that the author has yet actually show us the face of the killer lets us know that blond guy is possibly not the killer. ON THE OTHER HAND, her brother tbh his hair fits in with that “auburn hair color” statement and it’s a 0% possibility that FL is the killer bc the ghosts would probably haunt her rather than come to her for help. And the fact that the killer is some way and some how getting into their home is sus bc mind you the night before the skin was in her room, she made sure to check the doors and windows so how is it that killer somehow got in. What if the brother also got a part of his mother, not the part where she can see and hear things but the bad part where she acts upon it and fl got the hearing and seeing part. And tbh I feel like he knows that the ghosts are speaking to FL bc there was no need to act the way did when she was in the room with him that one chapter. Any ways lemme go cleanse my mind bc this shit is scary as hell (●￣(ｴ)￣●)