An alleged female member of Isis’s “morality police” has been charged in Germany over the killing of a young girl she and her husband held as a slave in Iraq.

The suspect, a 27-year-old German identified only as Jennifer W in line with local privacy rules, was deported from Turkey to Germany in 2016.

She was arrested in June and has now been charged with murder and committing a war crime over the five-year-old’s death.

Federal prosecutors said she patrolled parks in the Iraqi cities of Fallujah and Mosul in 2015, ensuring women adhered to Isis dress and behaviour codes.

They alleged she and her husband bought the girl as a slave. The husband left the girl chained outdoors as punishment for wetting her mattress. Jennifer W allegedly did nothing to prevent her dying of dehydration.

In an indictment made public on Monday, police alleged the woman left Germany in August 2014 to join Isis. She arrived in Iraq the following month via Turkey and Syria and “immediately joined the decision-making and command structure” of the terrorist group.

Between June and September 2015, she allegedly patrolled parks armed with an assault rifle, a pistol and an explosive vest. She received a monthly salary from Isis of up to $100 (£79).

That summer, she and her husband bought the girl, who was being held as a prisoner of war, the indictment says, and kept her as a housebound slave.

The group's so-called caliphate across Iraq and Syria was dismantled after gruelling fighting across Iraq and Syria last year (AFP/Getty)

In a statement published on the German public prosecutor’s website, the indictment continued: “After the girl had fallen ill and wet herself on a mattress, the husband of the accused chained the girl as punishment in the open air and had the child dying of thirst in the scorching heat.

“The accused let her husband do it and did nothing to save the girl.”

In January 2016, Jennifer W allegedly visited the German embassy in Ankara, the Turkish capital, and applied for new identity documents – possibly because her original documentation may have been destroyed upon joining Isis.

She was arrested by Turkish security services after leaving the embassy and deported to Germany a few days later.