Taha Al-Jumailly, 29, was found guilty of genocide, crimes against humanity resulting in death, war crimes, aiding and abetting war crimes and bodily harm resulting in death after joining the so-called Islamic State group in 2013.

Proceedings were suspended as the defendant passed out in court when the verdict was read out.

The Yazidis, a Kurdish-speaking group hailing from northern Iraq, have for years been persecuted by IS militants who have killed hundreds of men, raped women and forcibly recruited children as fighters.

In May, UN special investigators reported that they had collected "clear and convincing evidence" of genocide by IS against the Yazidis.

"This is the outcome every single Yazidi and all genocide survivors were hoping to see," Natia Navrouzov, a lawyer and member of the NGO Yazda, which gathers evidence of crimes committed by IS against the Yazidis, told AFP after the verdict.

"Today is a historical day for humanity and the Yazidi genocide enters finally the history of international criminal law. We will make sure that more trials such as this take place," she said.

- Torment -

Prosecutors say Al-Jumailly and his now ex-wife, a German woman named Jennifer Wenisch, "purchased" a Yazidi woman and child as household "slaves" while living in then IS-occupied Mosul in 2015.

They later moved to Fallujah, where Al-Jumailly is accused of chaining the five-year-old girl to a window outdoors in heat rising to 50 degrees Celsius (122 Fahrenheit) as a punishment for wetting her mattress, leading her to die of thirst.

In a separate trial, Wenisch, 30, was sentenced to 10 years in jail in October for "crimes against humanity in the form of enslavement" and aiding and abetting the girl's killing by failing to offer help.

Identified only by her first name Nora, the child's mother testified in both Munich and Frankfurt about the torment visited on her daughter.

She also described being raped multiple times by IS jihadists after they invaded her village in the Sinjar mountains in northwestern Iraq in August 2014.

- 'Clear message' -

The mother was represented by a team including London-based human rights lawyer Amal Clooney, who has been at the forefront of a campaign for IS crimes against the Yazidis to be recognised as genocide, along with former Yazidi slave and 2018 Nobel Peace Prize winner Nadia Murad.

Although Clooney did not travel to Munich or Frankfurt, she called Wenisch's conviction "a victory for everyone who believes in justice," adding that she hoped to see "a more concerted global effort to bring ISIS (another acronym for IS) to justice".

Murad has called on the UN Security Council to refer cases involving crimes against the Yazidis to the International Criminal Court or to create a specific tribunal for genocide committed against the community.

Germany, home to a large Yazidi community, is one of the few countries to have taken legal action over such abuses.

German courts have already handed down five convictions against women for crimes against humanity related to the Yazidis committed in territories held by IS.

Prosecutors in Naumburg on Tuesday charged a German woman named as Leonora M. with aiding and abetting crimes against humanity after she and her IS husband enslaved a Yazidi woman in Syria in 2015.

Germany has charged several German and foreign nationals with war crimes and crimes against humanity carried out abroad, using the legal principle of universal jurisdiction which allows offences to be prosecuted even if they were committed in a foreign country.

The trial of Al-Jumailly "sends a clear message", Navrouzov told AFP.

"It doesn't matter where the crimes were committed and it doesn't matter where the perpetrators are, thanks to the universal jurisdiction, they can't hide and will still be put on trial."