One of the Islamic State’s primary tactics in cementing control over the population is mass executions: literally rounding people up based on sectarian affiliation or political ideology and gunning them down. From Libya to Syria to Iraq, ISIL militants have executed thousands of people on charges ranging from being a government supporter to worshiping Islam the wrong way. In February, ISIL militants staged a taped execution of Egyptian Christians on the beaches near Tripoli, and performed a similar act of inhumanity in April when they killed roughly 30 Ethiopian Christians.

Eight months prior, ISIL slaughtered 700 men from the Sheitaat tribe in the Syrian province of Deir ez-Zor in what can only be described as an attempt to punish any tribal forces in the area seeking to oppose its dominance. And, in the organizations most monumental and unprecedented act of terrorism, roughly 1,300 Iraqi troops who were seized at the Speicher air base in Tikrit during ISIL’s sweep towards Baghdad last June were transported in trucks, sprayed with gunfire, and dumped in several mass graves.

In all of these executions, ISIL’s purpose was the same: demonstrate to the people under its rule that any act of treachery or resistance will be met with a tenfold response. Instilling fear into the hearts of the population is an effective way of deterring opposition. Just ask the citizens of Mosul.

Daniel R. DePetris is an analyst at Wikistrat, Inc., a geostrategic consulting firm, and a freelance researcher. He has also written for CNN.com, Small Wars Journal and The Diplomat.

Image: Wikimedia/U.S. Forces Iraq Photo by Spc. Timothy Koster