Lady Macbeth and the apparent suicide
Lady Macbeth may have not committed suicide as Malcolm put it: "his fiend-like queen, who, as 'tis thought, by self and violent hands took off her life." I believe that someone else could have killed her and didn't admit to the crime. Suspect one is Malcolm himself, for he was the one to speak about Lady Macbeth committing suicide, so why not blame him? Macbeth was his enemy after all and Malcolm knew that Macbeth thrived with Lady Macbeth by his side, so if he could take her out of the equation, then Macbeth might give up or lose hope. Suspect two is the gentlewoman, because she is the one to notice that Lady Macbeth is going crazy. With this fact in mind, she started to spread the word and made people lose their loyalty to the royalty. Since she was so close to the queen, she could have easily pulled off another Duncan murder, this time with Lady Macbeth as the victim and the suspect.