Synopsis As Introduced Amends the Criminal Code of 2012. Reinstates the death penalty if at the time of the commission of the offense the person was 18 years of age or older and the person purposely caused the death of 2 or more human beings without lawful justification or the victim was a peace officer or firefighter killed in the course of performing his or her official duties, either to prevent the performance of the person's duties or in retaliation for the performance of the person's duties, and the person knew that the victim was a peace officer or firefighter. Provides a person is legally accountable for the conduct of another in the commission of death penalty murder only when: (1) having the purpose to cause the death of another human being without lawful justification, the person commands, induces, procures, or causes another to perform the conduct; or (2) the person agrees with one or more other persons to engage in conduct for the common purpose of causing the death of another human being without lawful justification, in which case all parties to the agreement shall be criminally liable for acts of other parties to the agreement committed during and in furtherance of the agreement. Amends the Code of Criminal Procedure of 1963 and Unified Code of Corrections to make conforming changes. Effective immediately.