Jinrui Saikyou no Venice

The fifth instalment of the Saikyou Series.
The most strongest heroine in 10,000 years.
Aikawa Jun, a famous detective and Humanity's Strongest Contractor.
A non-stop mystery about two beautiful women and a serial killer.
Don't interfere with my journey. I'll kill you.
Aikawa Jun, Humanity's Strongest Contractor.
She is assigned to accompany Jikumoto Miyori, a nineteen-year-old authority on psychology, on a field investigation. It was supposed to be a fun trip with the addition of the overly perfect maid, Handa Rei. However, at their destination in Venice, a couple of tourists and famous actresses are brutally murdered one after another via drowning.
The "drowned killer" has his claws on these women, too—?!
(Source: Kodansha, translated)