[url=http://www.huffingtonpost.com/2013/04/16/pressure-cooker-bombs-history_n_3094193.html]Article[/url] [quote]Homemade bombs built from pressure cookers, a version of which was used in the Boston Marathon bombings, have been a frequent weapon of militants in Afghanistan, India and Pakistan. Al-Qaida's branch in Yemen once published an online manual on how to make one, urging "lone jihadis" to act on their own to carry out attacks. A person briefed on the investigation told The Associated Press that the explosives were fashioned out of pressure cookers and packed with shards of metal, nails and ball bearings to inflict maximum carnage. The SITE Monitoring Service, a U.S. independent group tracking militant messaging online, noted that Islamic extremists are not the only ones paying attention to the al-Qaida magazine: White supremacists have also circulated copies on their web forums. They found "Inspire" and "other al-Qaida manuals beneficial for their strategies," it said.[/quote] I'd like to know what kind of explosives were in the bomb. Dynamite? C4? Or something as common as match heads? Whoever did this made it hard for investigators by using a bomb that can be made using directions from the Internet, it means that the FBI can't narrow down the list of suspects from the bombs alone.