He killed innocent people

An anonymous letter: It said: Dear Brigadier General Mahmoud, many people have challenged you to identify the killer, but I decided to take on a new kind of challenge with you. This time, if you do not know the killer, you will turn into a killer. How? I will tell you about a murder... and when you suspect an innocent person... I will kill him... or more correctly... you will cause him to be kille...