The #US identification of #CrocusCityHall as a potential target — a fact that has not been previously reported — raises new questions about why Russian authorities failed to take stronger measures to protect the venue, where gunmen killed >140 people & set fire to the bldg. A branch of the #IslamicState took credit for the attack, the deadliest in #Russia in 20 yrs. #UnitedStates ofcls publicly said the group #ISISK, “bears sole responsibility,” but #Putin has tried to pin the blame on #Ukraine.