throughout the day today. >> ed, thank you so much. also, new this morning, chilling images. cnn's obtained a video that shows the boston bombing suspects working out at a gym, this is just 72 hours before the bombs went off. security cameras at the y crew mixed martial arts center show the tsarnaev brothers arriving with a friend before 2:45 p.m. on friday, april 12th. the manager says tamerlan seen wearing a hat there looked different. he shaved off his beard he had for a while. that could have been a sign of things to come. >> shaving the beard may be a way to blend in, not to attract scrutiny from security services in carrying out the boston attacks. we have seen, in part, terrorism cases, past plots, western middletons shave their beards off before plotting attacks. >> before they get started, tamerlan is seen in an argument