In 1979, Chase stood trial on six counts of murder. In order to avoid the death penalty, the defense tried to have him found guilty of second degree murder, which would result in a life sentence. Their case hinged on Chase's history of mental illness and the suggestion that his crimes were not premeditated.
On May 8, 1979, the jury found Chase guilty of six counts of first degree murder and, rejecting the argument that he was not guilty by reason of insanity, sentenced him to die in the gas chamber. His fellow inmates, aware of the extremely violent nature of Chase's crimes, feared him, and according to prison officials, often tried to persuade Chase to commit suicide.