In "Macbeth" by William Shakespeare, did Macduff ever suspect Macbeth for killing Duncan or Banquo? 10 PTS!!!!?

I'm writing a literary ysis over Macbeth and I'm wanting to know if macduff ever suspected Macbeth for killing Duncan and/or Banquo? If so, can you give me a act, scene, and line OR a website where I can go to that has info on this??? Thanks! :)