The second bomb was in a metal container, but it was unclear whether it was in a pressure cooker as well, the FBI said.

CNN: Healing in Boston as investigators seek 2 seen near bombing

The second bomb was also housed in a metal container, but it was not clear whether it too was in a pressure cooker, the FBI said.

CNN: Sources: Possible suspect sought in Boston bombing

The second bomb was also housed in a metal container, but there's not enough evidence to determine whether it was also in a pressure cooker, the agency said.

CNN: Boston Marathon attack: More details, more questions