 In reality, Elmo Patrick Sonnier and Robert Lee Willie, both inmates  on whom Sean Penn (I) (qv)s character Matthew Poncelet is based  on, were executed by the electric chair in Louisiana in 1984; by  1993, Louisiana switched that penalty to lethal injection as the  most humane way to execute. Both Tim Robbins (I) (qv) and  Helen Prejean (qv) opted to use lethal injection in the film  instead of the electric chair because, according to Prejeans  interview, "We dont want to give people the moral (of the most  humane death) out whereby people could say Oh well, we used to do  electrocution but thats too barbaric so now we are humane and  inject them."