Is Unknown coming back?

The story begins in a quiet small town where serial murders suddenly begin to occur. The victims are drained of blood, there are no leads, and the case has remained unsolved for five years.
Yamihara Kokoro is a top—notch reporter for a weekly magazine, living with a secret she can't tell anyone about.
Asada Toramatsu is a local policeman who also has his own secret.
They have been in a relationship for a year and are starting to think about marriage, but the secrets they keep prevent them from moving forward in the relationship. And at the moment when Kokoro decides to reveal his secret to Toramatsu, a terrible murder takes place in the city again, involving the couple in a series of strange events.