Complex sentence: Convined that her father was involved he would not let go till another murderer confessed to the crime in the episode Ghosts and only after the father had to testify against the second culprit did Fontana relenquish the idea the Mister Dolan was involved.
Split into simpler sentences: Convined that her father was involved, Fontana would not let go of the case until another murderer confessed to the crime in the episode'Ghosts'. Only after the father had to testify against the second culprit did Fontana relinquish the idea that the victim's father was involved.