"Juan Corona, a Mexican-American, was sentenced to 25 consecutive life terms for murdering 25 migrant farm workers he had hired, killed, and buried in 1970-1971 near Feather River, Yuba City, Calif., on February 5, 1973, at Fairfield, Calif."The Longest Prison Sentences. "The longest recorded prison sentences were ones of 7,109 years, awarded to 2 confidence tricksters in Iran (formerly Persia) on June 15, 1969. The duration of sentences are proportional to the amount of the defalcations involved. A sentence of 384,912 years was demanded at the prosecution of Gabriel March Grandos, 22, at Palma de Mallorca, Spain, on March 11, 1972, for failing to deliver 42, 768 letters.
For some sentences I think that killing them might just be cheaper... And quicker..