Even worse, it was the female ISIS members telling them this.

Via The Sun:

A YAZIDI sex slave has described how ISIS terrorists would tell the captives they had to rape them to convert them to Islam.

The unnamed victim also described how the sick thugs would grope the breasts of girls they had captured to see if they were old enough to be raped.

Her harrowing testimony was featured in the report Trafficking Terror, released by the Henry Jackson Society think-tank.

She said that Islamic State members would touch the chests of captured girls to see whether they had grown breasts.

If they had breasts, they could be raped, if not, they would wait three months to check again.

She added: “The men used to rape up to seven girls in one room, so everybody could see what was going on; the screaming was up to the skies.

Once she tried to escape and was raped by six men in one night as a punishment.

The Yazidi woman said female ISIS terrorists would tell captives: “You have to be raped to become a Muslim.”