Since Fujisaki was killed in the same way as Genocider Syo, it adds to my suspicions of him being male because every other victim was male. Serial killers usually kill their victims in a similar way and some may even have OCD preventing them from doing it any other way. The scissors are missing, but Fujisaki has been crucified and the message bloodbath fever has been used. If
Syo really does have dissociative identity disorder, they might also suffer from memory loss during that state. This will make identifying the killer even more difficult.
I don't think there is enough information to completely identify the culprit, just make assumptions. I need to know more about what they were doing during the time of the murder to be completely sure.