In 2014, al-Hashimi officially left al-Qaeda, reaffirming his loyalty to ISIL (which had previously operated as al-Qaeda's Iraqi branch). He played a key part in ISIL's capture of Mosul in June 2014. He was one of the main ISIL leaders who orchestrated the genocidal mass killings of Yazidis during the Sinjar massacre in August of that year. By this point, he had risen to deputy of Abu Bakr al-Baghdadi.