The Islamic State group used the promise of religiously sanctioned rape to lure young men with a history of sexual violence into its ranks, a new report to be released by a British think-tank and reported Monday in The Guardian said.

According to the soon-to-be-released analysis by the conservative Henry Jackson Society, there was an indication of a “relationship between committing terrorist attacks and having a history of physical and/or sexual violence.”

The report said that the promise of what The Guardian described as a "theology of rape" played a key role in “attracting, retaining, mobilizing and rewarding fighters.” The promise of sexual violence is especially potent, the report said, on young men from conservative Muslim communities were casual sex is verboten.

One example cited in the report was of a British youth called Ondogo Ahmed who was convicted of rape and fled to Syria to join ISIS to avoid his eight year prison sentence. Another one referenced by The Guardian was a former bouncy castle salesman called Siddhartha Dhar that was described by an ISIS-survivor as playing a key role in the group's persecution of the Yazidi minority, with Dhar reportedly taking a number of Yazdis as his personal slaves.

“These cases indicate an existence of a type of terrorism that is sexually motivated, in which individuals with prior records of sexual violence are attracted by the sexual brutality carried out by members of Islamic State,” The Guardian quoted one of the report's authors as saying.

Islamic State militants have killed, raped and enslaved thousands of Yazidis since 2014, accusing them of being devil worshippers and forcing over 400,000 of the religious minority to flee their homes in northern Iraq.

Yazidi campaigners, including Nobel Peace Prize nominee Nadia Murad Basee Taha, have been pushing for international justice for the crimes committed against them by Islamic State.

According to the United Nations, the Sunni militants enslaved about 7,000 women and girls in 2014, mainly Yazidis whose faith blends elements of Christianity, Zoroastrianism and Islam, and is still holding 3,500, some as sex slaves.

The United States, the European Parliament and the Council of Europe have all described the Islamist militant group's actions as genocide.