▁exact ▁date ▁of ▁his ▁death . ▁The ▁most ▁common ▁account ▁is ▁that ▁he ▁died ▁of ▁natural ▁causes ▁in ▁ 1 9 4 5 ▁while ▁serving ▁his ▁sentence ▁at ▁U c ci ard one ▁prison ▁in ▁Pal ermo . ▁Italian ▁author ▁Pet acco ▁found ▁evidence ▁for ▁his ▁ 1 9 7 2 ▁book ▁on ▁Joe ▁Pet ros ino ▁that ▁Cas cio ▁Fer ro ▁may ▁have ▁died ▁of ▁de h yd r ation ▁in ▁the ▁summer ▁of ▁ 1 9 4 3 . ▁According ▁to ▁Pet acco , ▁Cas cio ▁Fer ro ▁was ▁left ▁behind ▁in ▁his ▁cell ▁by ▁prison ▁gu ards ▁while ▁other ▁in m ates ▁were ▁ev acu ated ▁in ▁advance ▁of ▁the ▁Al lied ▁invasion ▁of ▁Sic ily . ▁However , ▁according ▁to ▁historian ▁Giuseppe ▁Carlo ▁Mar ino , ▁Cas cio ▁Fer ro ▁was ▁transferred ▁to ▁another ▁prison ▁in ▁Poz zu oli ▁in ▁ 1 9 4 0 , ▁and ▁the ▁oct ogen arian ▁was ▁left ▁to ▁die ▁during ▁an ▁Al lied ▁bomb ard ment ▁of ▁that ▁prison ▁in ▁ 1 9 4 3 ▁( other ▁sources ▁mention ▁ 1 9 4 2 ). ▁According ▁to ▁La ▁St ampa , ▁Cas cio ▁Fer ro ▁died ▁on ▁ 2 0 ▁September ▁ 1 9 4 3 , ▁in ▁the ▁prison ▁on ▁the ▁island ▁of ▁Pro cida . ▁ ▁For ▁years , ▁a ▁sentence ▁believed ▁to ▁be ▁car ved ▁by ▁Cas cio ▁Fer ro ▁was ▁leg ible ▁on ▁the ▁wall ▁of ▁his ▁U c ci ard one ▁cell : ▁" Pr ison , ▁sick