The Islamic State group has crushed a rebellion plot in its stronghold city of Mosul in Iraq, Reuters reported Friday.

The conspiracy was reportedly lead by one of Islamic State leader Abu Bakr al-Baghdadi's own aides, who along with 57 others, were executed for treason. The accused were drowned and their bodies dumped in a mass grave located somewhere in the barren outskirts of the city. The militants also known as ISIS responded to inquiries by family members regarding the whereabouts of their loved ones by refusing to provide any details except for a list of names of the "apostates" and indicating that they  could not be buried in Muslim cemeteries.