The Islamic State (ISIS/ISIL) group’s master of coin was killed on Tuesday in “a booby trap ambush” on his way back to Mosul, Iraq, after he participated in opening a prison for women who refuse to engage in “sexual jihad,” Kurdish news service Rudaw has learned.

“ISIS Finance Minister Mohammed Zaalan al-Afari was killed in a booby trap ambush on the Gayara-Mosul road  after he took part in the opening of a women’s prison for those not committed to sexual jihad,” Saeed Mamuzini, a spokesman for the Kurdistan Democratic Party’s (KDP) 17th branch in Mosul, told Rudaw.

“Sexual jihad is a controversial practice within jihadi groups where women voluntarily offer themselves in a sexual comfort role to fighters,” explains the report.

Four other ISIS jihadists were killed in the ambush. According to Mamuzini, the Mosul Independent Youth claimed responsibility for the attack.

Mosul is considered an ISIS stronghold.

Rudaw notes that “Afari was an Iraqi army officer prior to joining extremist jihadi groups in 2004” and “he allegedly had close ties with the Islamic State’s Caliph Abu Bakr al-Baghdadi and slain Al-Qaida in Iraq leader Abu Musab al-Zarqawi.”

The Telegraph reports that ISIS has begun minting its own currency, dubbed “Islamic dinar.” One gold “Islamic dinar” is worth $139, the group claims.