“Someone knows who did this. Cooperation from the community will play a crucial role in this investigation,” said DesLauriers.
Two blasts ripped through the Back Bay crowd seconds apart on Monday just before 3 p.m. Early indications are that the bombs had a basic explosive element, such as gunpowder or residue from match heads, placed inside common pressure cookers. Nails or ball bearings were added to create shrapnel.
Pictures from a law enforcement bulletin obtained by the Associated Press and Reuters showed pictures of mangled pressure cooker scraps, scraps of black nylon, a circuit board, and a battery with wires attached.
DesLauriers declined to speak publicly about this evidence. But news reports indicate that the FBI believes it may have recovered enough physical remains of the bombs to start the crucial business of reconstructing where parts came from and how they were assembled.
According to The New York Times, one of the pressure cooker scraps is inscribed “6L,” for six-liter capacity. The Spanish company Fagor is one firm that makes cookers identified with such a stamp. It sells 50,000 of them in the US every year, the Times reported.