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)