Oh my gosh. You would kill her because she lied? Your version of justice sounds much like vigilante thinking.
How about manslaughter or child endangerment? No death penalty there. Legal does not always equate to Justice. Casey was rewarded for lying and this reasoning by the jury is now legal history for other criminals to invoke when needed. Casey walks because she lied, and lied, and then there were more lies from her and her family. She did not testify and tell her side of the story for fear of a conviction. Her child is dead because one way or another Casey was negligent in protecting Caylee from danger. BTW, I would not know how or what a vigilante thinks, perhaps you could enlighten me?