NEW : Authorities ask federal and state agents to help identify two men seen in photos . The FBI is asking for the public's assistance identifying these men. : The men are of `` high interest '' in the probe into the Boston Marathon blasts . NEW : One of the men is seen in photos carrying a black backpack , an official says . An FBI official earlier said that authorities believe the bombs were placed inside a black nylon backpack or bag . 3 people were killed and about 180 injured when 2 bombs went off near the finish line .
NEW : Authorities ask federal and state agents to help identify two men seen in photos . The FBI is asking for the public's assistance identifying these men. : The men are of `` high interest '' in the probe into the Boston Marathon blasts . NEW : One of the men is seen in photos carrying a black backpack , an official says . 3 people were killed and about 180 injured when 2 bombs went off near the finish line .