Réponse :

A private investigator is looking for serial killer .  

On the wall he sees a finger print .  

And on the ground, he sees that it is a bullet .

But the victim did not die by a gun but by a dager .

The Private investigator believes serial killer shot before fleeing .  

Using bloodstains at the scene of the crime, the serial killer was identified and handcuffed.

Currently the serial killer is in prison .