Original: Smerdyakov claims that Ivan was complicit in the murder by telling Smerdyakov when he would be leaving Fyodor's house, and more importantly by instilling in Smerdyakov the belief that in a world without God "everything is permitted."
Simplified: Ivan decides that Dmitry has killed his father, until he visits Smerdyakov again â "and Smerdyakov openly admits that he killed Fyodor Pavlovich. Smerdyakov also says that he was able to do this because of Ivanâ s ideas that â everything was allowed.