It can be of any country. I wanna watch something where the killer hides their identity and basically pretends to be a normal person. Kind of like a double life thing.
The recent one is Anata no Ban desu. It's Japanese but still continues in second season now (still airing) so we don't know yet the real culprit.
Tunnel (the drama)
Kaito Yamaneko
Zettai Reido S3
Miss Sherlock
Try :
Kill It
Hello Monster
Come And Hug Me
I hear Your Voice.
