Nolanalysis - A simple Observation.

The young man : I din’t kill her. I din’t kill anyone. He killed them all. (Following)

Leonard Shelby : John G raped and murdered my wife. Find him and kill him.(Memento)

Will Dormer : I din’t kill my partner by knowledge. There was fog, I couldn’t see.(Insomnia)

Bruce wayne/Batman : someone killed my parents.(The Dark Knight Trilogy)

Alfred Borden : I don’t know which knot I tied. I din’t kill her.(The Prestige)

Dom Cobb : My wife committed suicide. I din’t kill her.(Inception)