What murders does lady macbeth allude to in her sleep?

In Act 2 Scene 2, Macbeth [c. 1014-August 15, 1057] stabs King Duncan I [d. August 14, 1040] and his two royal chamberlains to death. He is unhinged by the bloodied corpses and crime scene. He hears warning voices of sleepless nights for the rest of his life. One such voice accuses him, 'Macbeth does murther sleep...' [Line 36].