this morning there are new questions about what and when the nfl knew about the brutal video of ray rice striking his then fiancee, the nfl hired fbi director robert muller to lead an independent investigation into how the league handled the evidence in the case. >> the initial incident launched a broader domestic violence problem in the nfl into the spotlight. now women's rights groups are calling for the league commissioner to resign. abc's ryan smith has more. reporter: it was the blow that started everything. and a commissioner playing defense in his first comment since the video of nfl player ray rice striking his then fiancee janay palmer made public monday by tmz, roger goodell admitted on "cbs this morning" the league has until now failed to properly address domestic violence within its ranks. >> absolutely. we are saying. we have a problem.