abb at ical , ▁being ▁replaced ▁by ▁Lie v ▁Sch rei ber , ▁as ▁Michael ▁Ke pp ler , ▁who ▁developed ▁a ▁small ▁story ▁arc ▁through ▁" S weet ▁Jane ," ▁" Red rum ," ▁and ▁" Me et ▁Market ." ▁Also ▁in ▁ 2 0 0 7 , ▁the ▁character ▁appeared ▁in ▁a ▁two - part ▁c ros so ver ▁with ▁another ▁CBS ▁series , ▁Without ▁a ▁Trace . ▁It ▁was ▁the ▁sixth ▁episode ▁of ▁the ▁sixth ▁season , ▁entitled ▁" Where ▁and ▁Why ." ▁The ▁plot ▁of ▁the ▁c ros so ver ▁involved ▁a ▁serial ▁k iller ▁that ▁had ▁el ud ed ▁capture ▁in ▁Nev ada ▁and ▁had ▁escaped ▁to ▁New ▁York ▁City . ▁Gil ▁Gr iss om ▁was ▁brought ▁in ▁to ▁assist ▁in ▁the ▁app reh ension . ▁ ▁Character ▁background ▁ ▁Early ▁life ▁ ▁Gr iss om ▁was ▁born ▁as ▁an ▁only ▁child ▁to ▁a ▁middle - class ▁family ▁in ▁Santa ▁Mon ica , ▁California . ▁Gr iss om ' s ▁father ▁taught ▁bot any ▁at ▁a ▁local ▁college ▁and ▁passed ▁his ▁enthus ias m ▁for ▁natural ▁sciences ▁onto ▁his ▁son . ▁His ▁father ▁died ▁when ▁Gr iss om ▁was ▁nine ▁years ▁old . ▁Gr iss om ▁rec alls ▁the ▁day ▁his ▁father ▁died ▁to ▁Catherine ▁Will ows ▁in ▁the ▁episode ▁" St ill ▁Life ," ▁" He ▁came ▁home ▁from ▁school , ▁one ▁hot ▁hum id ▁day , ▁laid ▁down ▁on ▁the ▁c ouch . ▁I ▁was ▁watching ▁TV , ▁my ▁mom ▁brought ▁in ▁some ▁cold ▁drink s