>> by 2006, prison doctors had finally diagnosed nathan as bipolar and put him on the powerful drug, lithium. once medicated, nathan's behavior on death row changed radically, and he became a model prisoner. >> he was an entirely different person from the young man even that i knew. so it certainly has to be a part of why he did what he did. >> as nathan's appeals were being reviewed by the courts, a movement to fully ban capital punishment in colorado was picking up speed. >> i think that america has hopelessly entangled two concepts. one is justice, and the other is vengeance. and we need to untangle those. >> with polls showing nationwide support for the death penalty dwindling, a bill was introduced in the colorado state legislature to outlaw executions. >> we just felt strongly that we needed to start this debate. we needed to put it out there.