I think it is worth observing that Saddam was tried under Iraqi procedures, for Iraqi, not international, crimes. Iraqi law provides for the possibility of the death penalty. The court chose to impose that penalty, upheld by the appropriate appellate body.
That's not "murder". You may disapprove of the verdict, or disapprove of the sentence, or the finding on appeal, but "murder", no. The word "murder" has a meaning in law, and it's not just an imposed death of which you disapprove.