[zzhk]

Originally Posted by monir

In this story....

Spoiler for Ending for one of Agatha Christie book that I can't remember. Please don't click if you don't want to be spoiled:

Hercule Poirot is sickly and on a wheel chair with limited mobility. He comes across several incident where seemingly normal individual are killing people. Then Poirot starts noticing a pattern where every one of those killers talked to one individual at some point. What he noticed was how that individual did nothing more than talking to those potential murderers who eventually goes on to killing someone. After a lot of reflection, Poirot comes to the conclusion that there is really nothing he can do to convict the guy through the legal system. So the next best thing was to kill the guy himself. Which he did, and then he turns the weapon to himself. The story is pretty much a narrative of the account by Hasting who recalls the events.

I still can't remember the name of the book, but the villain in Psycho Pass pretty much falls into the same category.

Curtain: Poirot's Last Case