Alixus is the leader, right? Well, that's simple. Arrest and try her for multiple counts of murder, attempted murder, manslaughter, kidnapping, sabotage of a starship, assault and battery, conspiracy to commit all of the above, and grand theft runabout. Oh, and failure to comply with Federation medical regulations for the vaccination of minors. Then once she's convicted you stick her in New Zealand or some other rehab/detention facility until she's no longer nuts.