Al-Hashimi was an Iraqi security analyst, who was a leading expert on extremist groups, particularly the Islamic State. He was also a specialist in armed-group networks with close contacts among top Iraqi decision-makers. Al-Hashimi was an advisor to governments and frequently appeared in the media. According to the Associated Press, Al-Hashimi became an advisor to the Global Coalition to defeat ISIS.

After the defeat of ISIS in Iraq at the end of 2017, al-Hashimi shifted his attention to Iraq’s Iranian-backed militias that participated in fighting against ISIS.  After these militias began to use violence to defend their vested agenda, including regular rocket attacks on U.S. interests and assassination of political activists, al-Hashimi rebuked the Iranian-backed militias for operating outside the control of the state. In addition, he spoke out against government officials by criticizing them for not taking action against the militias targeting demonstrators during the Tishreen ‘October’ Movement protests in October 2019. 

On July 6, 2020, two gunmen riding a motorcycle shot and killed Hisham al-Hashimi outside his home in the Zeyouneh area of Baghdad. While no group has claimed responsibility for his assassination, friends and colleagues state that he had faced an increasing wave of threats from both the Sunni extremists in the Islamic State and the Shia Iranian-backed militias, specifically Kata’ib Hezbollah. 

A year after his killing, on July 16, 2021, Iraq’s Prime Minister Mustafa Al-Kadhimi said authorities arrested police first lieutenant Ahmad al-Kinani who confessed to the crime and belonged to an “outlaw group” without stating its name. However, a wide variety of sources assert that this group is Kata’ib Hezbollah.