ISIS Isn't the World's Deadliest Terrorist Group Boko Haram killed more last year By Newser Editors, Newser Staff Posted Nov 19, 2015 11:29 AM CST 113 comments Comments In this file photo, a woman walks past Nigerian soldiers at a checkpoint in Gwoza, Nigeria, a town newly liberated from Boko Haram. (AP Photo/Lekan Oyekanmi, File) (Newser) – The Islamic State might be the world's most notorious terrorist organization at the moment, but a new study reveals it is not the deadliest. According to the 2015 Global Terrorism Index, that grisly title belongs to Boko Haram, which was responsible for 6,644 deaths in Africa in 2014, compared to the total of 6,073 blamed on ISIS. Boko Haram is based in Nigeria but has expanded its attacks to neighboring countries, and, like ISIS, has declared a caliphate in its territory, notes the Atlantic. Perhaps most troubling of all, Boko Haram has declared allegiance with ISIS and is sometimes known as the Islamic State’s West’s Africa province, or ISWAP, reports the Independent.