A Muslim professor in Iraq reportedly paid the ultimate price for defending Christians under siege by the Islamic State of Iraq and Syria, a radical terror group that has taken control of Mosul, the nation’s second largest city.

Professor Mahmoud Al-Asali, a professor of law who works at the University of Mosul, “had the courage to make a stand against this brutal duress which he believes go against the Muslim commandments,” according to the Vatican Insider.

Snipers are covered in camouflage netting as Iraqi Shiites of the Mahdi Army militia loyal to cleric Moqtada al-Sadr vow to fight ISIS in a show of strength in a military parade on June 21, 2014 in the Sadr City district of Baghdad, Iraq. (Scott Peterson/Getty Images)

While details are limited and it is unclear what the professor said or did to catch the attention of militants, Ankawa.com, a website that documents atrocities against Iraqi Christians, reported that Al-Asali was killed by extremists Sunday.

“Dr. Al-Asali was assassinated because he objected to what these militants done of looting and burning the properties and possessions of Christian people in Mosul [sic],” claims a report on Ankawa.com.

Vatican Insider noted that Al-Asali would likely have known the risks of defending Christians, considering that ISIS was infamous for making those who defended Christians in the Syrian city of Raqqa pay dearly for disagreeing with the radical group’s tactics.

A Iraqi family who fled recent fighting near the city of Mosul prepares to sleep on the ground as they try to enter a temporary displacement camp but are blocked by Kurdish soldiers on July 3, 2014 in Khazair, Iraq. (Spencer Platt/Getty Images)

Christians in Iraq continue to suffer at the hands of radicals. Believers in the Iraqi city of Mosul — which is currently being held by the Islamic State of Iraq and Syria, a radical group seeking an Islamic caliphate — were recently given an ultimatum: convert to Islam, pay a tax or be put to death.

Historian Dr. Timothy Stanley recently decried the West’s silence over the plight of Christians, calling it “a war crime that, strangely, no one seems to want to talk about.”

(H/T: Vatican Insider)