M - A City Hunts a Murderer - Season 1 Episode 3 : Episode 3 2019

After finding the three children's corpses, the question arises: who is the third child? A necklace with an M on it is the only clue. The police are baffled. The pace of the serial killer leaves no time to breathe. To give a sense of security, the police starts to "clean up" the underworld. But the underworld isn't just sitting and waiting...