Stouffer was convicted and sentenced to death in 2003 after his first conviction and death sentence were overturned, but always maintained his innocence.
“My request is that my father forgive them. Thank you,” Stoutter reportedly told witnesses according to reports.
Members of the Pardon and Parole Board, prison reform activists and others have expressed concerns about executions carried out in Oklahoma and the state's ability to humanely execute people.
Oklahoma officials paused executions in 2015 when officials realized they received the wrong lethal drug. It was later learned the same wrong drug had been used to execute an inmate in January 2015. In April 2014, the execution of inmate Clayton Lockett took 43 minutes.