Death Penalty Deterrents?
That experience did not seem to have much of a deterrent effect. Within a year after being paroled the plumber committed murder, was sentenced to die and in a rather ironic twist, met his death in the gas chamber he helped build.
Former California Governor Edmund "Pat" Brown, in his book, Public Justice, Private Mercy, recounts how a plumber convicted of robbery was among the prisoners who built California's gas chamber at San Quentin. He helped to install it and watched test pigs die as the chamber's effectiveness was tested.