A study by the Combating Terrorism Center in the US has shown that an overwhelming majority of al-Qaida victims are, in fact, muslims. A leading al-Qaida ideologue for the terror network, Abu Yahya al-Libi, has developed his own theologically-based theory of collateral damage that allows militants to kill Muslims when it is unavoidable. Between 2004 and 2008, for example, al-Qaida claimed responsibility for 313 attacks, resulting in the deaths of 3,010 people. And even though these attacks include terrorist incidents in the West -- in Madrid in 2004 and in London in 2005 -- only 12 percent of those killed (371 deaths) were Westerners.
Put another way, between 2006 and 2008, non-Westerners were 38 times more likely to be killed by an al-Qaida attack than Westerners. “Since al-Qaida has limited capability to strike against its Western enemies, the group maintains its relevance by attacking countries with Muslim majorities,” the study concludes.
More is here.
Of course, the study does not take into account the Muslim victims killed by their fellow Muslims in Syria, Egypt, Afghanistan, Iraq and other Muslim countries. A study published by the British medical journal The Lancet reveals that at least 1003 suicide bombings caused civilian casualties in Iraq from 2003 to 2010. Sixty times as many civilians were killed as soldiers (12,284 vs. 200). This disparity is extreme by any standard, and evidence that civilians are not just the "collateral damage" of suicide bombers in Iraq but an intended target.
The worst enemy of a Muslim is... usually another Muslim.