Murder as a natural part of revenge and of ambition is somewhat of a theme in "Hamlet". The play, as the link below explains, is considered a "revenge tragedy". Hamlet's father is killed by Claudius, Prince Hamlet's uncle, because of Claudius' ambition (Act 3, sc. 3, ll. 53-55). The ghost of Hamlet's father then asks Hamlet to get revenge for him. Hamlet stews about this challenge for most of the play. Hamlet accidentally kills Polonius which drives Ophelia mad which leads to her death. In the duelling scene at the end of the play, Hamlet kills Laertes and finally Claudius, but not before Gertrude dies from drinking poisoned wine meant for Hamlet, and not before Hamlet himself is scratched by the poisoned tip of Laertes' sword. And we can't forget that Hamlet changed the orders Claudius had written asking the English to kill him and had Rosencrantz and Guildenstern killed instead with the reason that he said they had done everything Claudius asked of them. Lots of deaths, but really few premeditated murders. In that sense then, "murder" is not a theme of the play nearly as much as "revenge", "reluctance to take action", and "madness" are themes.