They also engage in public and mass executions of Syrian and Iraqi soldiers and civilians , sometimes forcing prisoners to dig their own graves before shooting lines of prisoners and pushing them in . Among the known mass executions of captured soldiers carried out by ISIL are those in Tikrit ( ISIS executed up to 1,700 Shia Iraqi Air Force cadets from Camp Speicher near Tikrit on 12 June 2014 ) , Al-Thawrah ( ISIS executed 250 Syrian soldiers captured at the Al-Tabqa air base between 27 and 28 August 2014 ) , Palmyra ( up to 280 Syrian soldiers and government loyalists were shot in the head or beheaded in a public square on 22 May 2015 ) , and Deir ez-Zor ( ISIS killed at least 300 Syrian soldiers , pro-government militiamen and their families on 16 January 2016 )
ISIS executed
Camp Speicher massacre
Islamic State of Iraq and the Levant