In September 2014, Ahmed al-Khafaji enlisted at the age of 25 in the Popular Mobilization Units, which were formed in accordance with a religious fatwa issued in June 2014 by the Shiite religious authority in Iraq, Grand Ayatollah Ali al-Sistani, with the aim of fighting the Islamic State (IS) following its invasion of the city of Mosul that month.
Arab and Iraqi Sunni parties claimed the fatwa incited Shiites to commit violence against Sunnis.
