A Knoxville lawmaker sponsored a new bill that would exempt convicted killers suffering from severe mental illness from the death penalty.

The bill would exempt someone from being sentenced to death if a previous medical diagnosis of a severe mental illness exists and the person was determined to be in a psychotic state at the time of the crime.

Individuals in question must be diagnosed with certain mental disorders defined as eligible by the American Psychiatric Association, including schizophrenia, schizo-affective disorder, bipolar disorder with psychosis, major depressive disorder with psychosis, and delusional disorder.

Attorneys would need to have an expert testify to the diagnosis. And a judge would determine in the pretrial hearings whether the case were appropriate for capital punishment.

In the case of a first-degree murder conviction, a defendant with severe mental illness would be eligible for life imprisonment without possibility of parole.