These laws narrow the class of offenders that may be punished by capital punishment. Both the elements of the crime of murder, which must be proven at the guilt phase of the trial, and sentencing factors, which must be proven at the penalty trial, serve to perform this narrowing function. Substantive differences exist in the definitions of capital murder, thereby affecting death penalty procedures. Death penalty schemes typically require that following a conviction for murder, proof be made of one or more statutory aggravating circumstances at the sentencing phase of the trial. The legislation also includes procedural safeguards to avoid error and the potential for arbitrary sentencing. These may include grand jury review of murder indictments, the death-qualification of potential jurors, and proof beyond a reasonable doubt of crime-related aggravating factors. Greater procedural protections typically are associated with guilt-phase narrowing statutes than with sentencing-phase narrowing statutes. The second part of this two-part article will focus on the substance of capital murder and review several issues related to it. Footnotes