Johnson was found guilty in the murder of 6-year-old Casey Williamson in 2002. Missouri Governor Mike Parson described his case as "one of the most horrific."
The Rev. Jeff Hood told Newsweek about his experience being in the execution chamber while Scott Eizember and Arthur Brown Jr. were put to death this year.
Jemaine Cannon, 51, is scheduled to receive a lethal injection Thursday morning at the Oklahoma State Penitentiary. This is the ninth execution since the state resumed lethal injections in 2021.