ri ppen ▁trial , ▁Sp ils bury ▁showed ▁himself ▁to ▁be ▁an ▁out standing ▁witness ▁for ▁the ▁pro sec ution , ▁easily ▁dealing ▁with ▁cross - ex am ination ▁by ▁the ▁junior ▁defence ▁bar r ister ▁and ▁demonstr ating ▁highly ▁effective ▁for ens ic ▁techniques . ▁ ▁Tri al ▁and ▁execution ▁ ▁Sed don ▁and ▁his ▁wife ▁became ▁the ▁chief ▁suspect s ▁in ▁what ▁was ▁by ▁now ▁a ▁murder ▁inqu iry . ▁During ▁their ▁trial ▁at ▁the ▁Old ▁Ba iley ▁the ▁pro sec ution , ▁led ▁by ▁the ▁Att orney ▁General , ▁Sir ▁R uf us ▁Isa acs , ▁proved ▁that ▁Margaret ▁Sed don ▁had ▁previously ▁bought ▁a ▁large ▁amount ▁of ▁fly paper , ▁which ▁contained ▁ar sen ic . ▁The ▁pro sec ution ▁suggested ▁that ▁the ▁poison ▁used ▁to ▁kill ▁Bar row ▁had ▁been ▁obtained ▁by ▁so aking ▁the ▁fly paper ▁in ▁water . ▁The ▁ren owned ▁bar r ister ▁Edward ▁Marshall ▁Hall ▁led ▁for ▁the ▁defence . ▁He ▁strongly ▁resist ed ▁all ▁claims ▁that ▁Bar row ▁had ▁been ▁poison ed , ▁claim ing ▁instead ▁that ▁she ▁had ▁died ▁by ▁taking ▁a ▁medical ▁prepar ation ▁containing ▁ar sen ic . ▁Despite ▁the ▁advice ▁given ▁by ▁his ▁Coun sel , ▁Sed don ▁ins isted ▁on ▁giving ▁evidence ▁in ▁his ▁own ▁defence ; ▁it ▁was ▁claimed ▁that ▁he ▁turned ▁the ▁j ury ▁against ▁himself ▁through ▁his ▁ar rog ant ▁and ▁cond esc ending ▁attitude . ▁C ertain ly , ▁his ▁case ▁was ▁not ▁helped ▁by ▁his ▁rid icul ous ▁claim ▁that ▁Bar row ▁might