The Islamic State's atrocities
After breaking away from al-Qaeda in early February 2014, the extremist Islamic group led by Abu Bakr al-Baghdadi called itself the Islamic State of Iraq and the Levant. Since then, it has gained control of wide regions in Iraq and Syria, including the city of Raqqa, which is now the group's de facto capital. The group has targeted cities and areas in northern Iraq and Syria and massacred hundreds of soldiers and residents, especially those who belong to minority tribes. You can read about the massacres here. In addition to the massacres, scores of hostages, including Westerners, have been killed by the Islamic State since then.
Here are some of the major incidents where the Islamic State killed the hostages.
SOURCE: The Washington Post.