The servants: Macbeth made the crime scene look like they killed King Duncan before he killed them.The King’s sons, Lennox and Malcolm: They had recently fled the country because they felt unsafe, which aroused suspicion about the possibility that they paid someone to kill their father.Macbeth: The Old Man suspected Macbeth because he had motive to kill and become King. There are also a few more people who could have committed the murder for one reason or another, although they are not prime suspects. They are: Macduff: Could become King if he killed King Duncan and Macbeth.Porter: He was drunk and wouldn’t have known what he was doing