Siren (2015)

Both japanese dramas are really complex and have a great plot about suspense.

If you love Gannibal, you will also love Siren..the thriller, psychological and suspense set high bar same like Gannibal

Build up trust with someone before carry out the plan bcoz the serial killer won't kill those he cannot gain trust from someone..it was mind-blowing and psycho.. HIGHLY RECOMMENDED!!

if you love the chemistry between Yuki and Kara in Siren, you absolutely need to watch Boku Unmei no HIto Desu. yes, the genres of both this shows are totally not related but you can see another types of characters played by Nanao and Kimura Fumino. I would like to see both of them on another shows again without complaint.

Both are excellent crime/investigation jdramas and both have Kimura Fumino as female lead.
Siren focuses more on the romance, the case is good and twisted. Ishi no Mayu has no romance but darker even more twisted cases.
both recommended

Both deal with a serial killer and the police officers who try and catch them.