A police forensic expert arrives at a blast site at a subway station in Santiago, Chile, Monday Sept. 8, 2014. A bomb exploded in the Chilean subway station injuring at least seven people, the most damaging in a string of bombs planted around the country’s capital this year.
In this Thursday, Feb. 6, 2014 file photo, civilians and security forces inspect the site of a car bomb attack in the Shaab neighborhood of Baghdad, Iraq. Car bombs are one of the deadliest weapons used by the al-Qaeda breakaway group that dominates the Sunni insurgency in Iraq, with coordinated waves of explosions regularly leaving scores dead in Baghdad and elsewhere across the country. (photo credit: AP Photo/Karim Kadim, File)
Instructor for al-Qaeda breakaway group detonates explosives by mistake during car-bomb demo at training camp near Baghdad