Duncan's murder, in the play Macbeth by William Shakespeare, was a complete catastrophe, and an unheard of action for the in which it was written. This deed, performed by Macbeth, cannot totally be blamed on the doer; Blame lies with other parties. The three witches are to blame. Their prediction of Macbeth becoming King sparked ambition in Macbeth, causing him to asphyxiate himself with the idea of this being a reality. Lady Macbeth is also at fault. Macbeth decides not to go ahead with the plan to kill Duncan but she, also becoming obsessed with the idea of Macbeth being king almost forces Macbeth into committing the crime. Macbeth played an instrumental role in the murder of Duncan. He, however being in sighted by others, was in full control of himself. He knew what he was doing and did it.
The Three witches could be blamed for the murder of King Duncan. When encountering Macbeth and Banquo, they made three predictions. One, being that Macbeth would become Thane of Cawdor, two, Macbeth becoming King of Scotland, and three Banquo's children becoming King's as well. They laugh this off, thinking that these witches are nothing more than crazy old bag's who were talking rubbish; incorrect. Not so soon after coming across these witches, was the first prediction realized. Macbeth was awarder Thaneship of Cawdor. This made him engage in thought about whether the second prediction, him becoming King could be true. A deep ambition in Macbeth was sparked, and a desire to become king grew great.
Due to this the three witches are partly to blame for Duncan's death, because they sparked a deep ambition in Macbeth to become king. If they had not told him this information, then Macbeth would not even have dreamt of murdering Duncan.
Lady Macbeth, Macbeth's wife, is at fault in this situation. When she found out about this prediction, she too was intent on Macbeth's progression to the throne. She became totally fixated and obsessed with this idea.