who must determine whether a defendant was insane at the time of a crime
Insanity defense The defense is based on evaluations by forensic mental health professionals with the appropriate test according to the jurisdiction. Their testimony guides the jury, but they are not allowed to testify to the accused's criminal responsibility, as this is a matter for the jury to decide. Similarly, mental health practitioners are restrained from making a judgment on the issue of whether the defendant is or is not insane or what is known as the "ultimate issue".[8]
Hung jury Juries in criminal cases are generally, as a rule, required to reach a unanimous verdict, and juries in civil cases typically have to reach a majority on some level. If a defendant has been found guilty of a capital offense, one that could result in the death penalty if the person is eligible, the opinion of the jury must be unanimous if the defendant is to be sentenced to death. Currently, two states, Oregon and Louisiana, do not require unanimous verdicts in criminal cases. Each requires a 10-2 majority for conviction, except for capital crimes: Oregon requires at least 10 votes out of 12 for felonies, but unanimity for first degree murder, and Louisiana requires all 12.