if she has been declared criminally insane (meaning, she is to be locked up in a psych ward for likely the rest of her days, isn't that pretty much the same as being in jail only she'll get the mental health attention she obviously needs so that someday perhaps she (and the rest of the world)will be able to understand what makes her mind work.
Remember justice is suppose to be about just that - justice - not revenge. Seems to me justice is served if she is behind locked doors, society is protected from her AND we have an opportunity to try and understand what makes people behave as she did. Much more productive then locking her up in a prison or sticking a needle in her arm.