You are probably the last person (except the killer) to see the owner alive. And you have noticed the disappearance of an antique weapon from the deceased's study. Should you tell the family of the deceased? After all, everyone knows your passion for fine weapons.
Ludwig asked you about antique arms dealers. You thought it was strange.
Henry had three gunshot wounds on his body. Obviously, the shooter was an amateur. An experienced shooter never doubts his shot - you already knew that.