▁grand ▁j ury ▁said ▁that ▁the ▁police ▁department ' s ▁ra id ▁was ▁" ill ▁conce ived " ▁and ▁that ▁there ▁were ▁many ▁errors ▁committed ▁during ▁the ▁post - raid ▁investigation ▁and ▁reconst ruction ▁of ▁the ▁events . ▁It ▁said ▁that ▁the ▁ref us al ▁of ▁the ▁surv iving ▁Black ▁Pan thers ▁to ▁co oper ate ▁ham per ed ▁the ▁investigation , ▁and ▁that ▁the ▁press ▁" im pro per ly ▁and ▁gross ly ▁ex agger ated ▁stories ". ▁▁ 1 9 7 0 ▁Civil ▁rights ▁law suit ▁In ▁ 1 9 7 0 , ▁the ▁surv iv ors ▁and ▁relatives ▁of ▁Ham pton ▁and ▁Clark ▁file d ▁a ▁civil ▁suit , ▁stating ▁that ▁the ▁civil ▁rights ▁of ▁the ▁Black ▁Pan ther ▁members ▁were ▁viol ated ▁by ▁the ▁joint ▁police / F BI ▁ra id ▁and ▁seeking ▁$ 4 7 . 7 ▁million ▁in ▁dam ages . ▁Tw enty - e ight ▁defend ants ▁were ▁named , ▁including ▁Ass istant ▁DA ▁Han ra han ▁as ▁well ▁as ▁the ▁City ▁of ▁Chicago , ▁Cook ▁County , ▁and ▁federal ▁govern ments . ▁It ▁took ▁years ▁to ▁get ▁to ▁trial , ▁which ▁last ed ▁ 1 8 ▁months . ▁It ▁was ▁reported ▁to ▁have ▁been ▁the ▁longest ▁federal ▁trial ▁up ▁to ▁that ▁time . ▁After ▁its ▁conclusion ▁in ▁ 1 9 7 7 , ▁Judge ▁Joseph ▁Sam ▁Perry ▁of ▁United ▁States ▁District ▁Court ▁for ▁the ▁Northern ▁District ▁of ▁Illinois ▁dismiss ed ▁the ▁suit ▁against ▁ 2 1 ▁of ▁the ▁defend ants ▁prior ▁to ▁j ury ▁deliber