Elmo Patrick "Pat" Sonnier (February 21, 1950 – April 5, 1984) was a convicted American murderer and rapist in Louisiana who was executed by electrocution at Louisiana State Penitentiary in Louisiana on April 5, 1984.
Sonnier was sentenced to death - with his younger brother, Eddie, sentenced to life in prison - on April 25, 1978, for the November 5, 1977, rape and murder of Loretta Ann Bourque, 18, and the murder of David LeBlanc, 17.
Sister Helen Prejean was asked to write to death row inmates as part of her Order's community outreach program and wrote to Sonnier.
She became his spiritual adviser and eventually wrote Dead Man Walking (1993) about her experience and her belief that the death penalty was morally wrong.