Qaeda illustrated a recent bomb-making article in its magazine Inspire, with a photo of what appears to be a backpack, left in one of the red chairs at Times Square.
It was Friday, September 10, 1976, almost exactly 25 years before 9/11, and a group of Serbo-Croatians were hijacking TWA flight 355, from New York to Chicago. Their aim was to gain attention to the Croatian independence movement. Their weapons were: pressure-cooker bombs.
While the hijackers never detonated the bombs, and in fact gave NYPD information for where to locate one of the bombs left in Grand Central Station, a police officer would eventually die in an effort to disarm the explosive.
The pressure-cooker bomb has been popular as a weapon of terrorists for a long time now, for a number of reasons;
A. It is inexpensive to construct.
B. It is simple to construct.
C. The materials one obtains to construct the explosive, common household items, will not raise red flags for law enforcement.
D. The pressure-cooker design amplifies the power of a small amount of explosive.
The bomb used in Boston seems to have followed the construction guidelines offered in the Qaeda English-language magazine, Inspire, which included an article in its premiere issue, entitled “Make A Bomb In The Kitchen Of Your Mom”, which gives explicit and easy-to-follow instructions for how to construct a pressure-cooker bomb.
Photos of remnants of the exploded Boston bomb, look very much like similar photos contained in the Qaeda bomb-making guide.