Complex sentence: The book was mentioned in Agatha Christie's mystery (Hercule Poirot series) novel "Five Little Pigs", when Poirot asks one of the suspects if she read the book at the time the crime was committed.
Split into simpler sentences: The book was mentioned in Agatha Christie's mystery (Hercule Poirot series) novel "Five Little Pigs". Where Poirot asked one of the suspects if she read the book at the time the crime was committed.