Complex sentence: Commissioner Gordon, however, remains in guilt over covering up Dent's killing spree, because Dent's attack on the Gordon family has caused the commissioner's divorce, thus he had succeeded of inflicting agony upon Gordon.
Split into simpler sentences: Commissioner Gordon, however, remains in guilt over covering up Dent's killing spree. Because Dent's attack on the Gordon family has caused the commissioner's divorce, thus he had succeeded of inflicting agony upon Gordon.