Complex sentence: In addition, he discovers that their grandfather has been dead for nine months and overhears the butler, John Amos, saying that Olivia has been leaving arsenic-covered food upstairs to kill the mice in the attic.
Split into simpler sentences: In addition, he discovers that their grandfather has been dead for nine months. He overhears the butler, John Amos, saying that Olivia has been leaving arsenic-covered food upstairs to kill the mice in the attic.