April 17, 2013 (Boston)—The FBI laboratory has analyzed pieces of  black nylon recovered from the finish line at the Boston Marathon and has determined that both explosives were placed in a dark-colored nylon bag or backpack.  

“The bag would have been heavy because of the components in it,” said Richard DesLauriers, special agent in charge of the Boston division of the FBI. The FBI, in conjunction with other agencies, is scouring databases andinterviewing eyewitnesses after securing the downtown area.  More than 2,000 tips have been received on the bombings, which killed three people and injured 176 on Monday.

“Importantly, the person who did this is someone’s friend, neighbor, coworker, or relative. We are asking anyone who may have heard someone speak about the marathon or the date of April 15 in any way that indicated he or she may target the event to call us. Someone knows who did this,” Agent DesLauriers stated in a press release sent to media nationwide.