After multiple attempts to leave Syria, four ISIS-linked women (often referred to as “ISIS brides”) and nine children have arrived back in Australia.

The government has long promised that if these women, who are Australian citizens and have Australia passports, came back, they would face criminal prosecution.

Now the Australian Federal Police has done just that. Two women who landed in Melbourne on Thursday were arrested and charged with crimes against humanity, including slave-related offences.

A third woman, who landed in Sydney, was arrested and charged with joining Islamic State (IS) and remaining in a declared conflict zone.

These prosecutions wade into uncharted legal territory in Australia. No one has been charged with international slavery offences before, and only one other person has been tried for the conflict zone offence.

Read more: Albanese is prioritising politics over the responsible handling of ISIS families, setting a dangerous precedent

Police have pressed charges against three women.

In Victoria, a 53-year-old, reportedly named Kawsar Abbas, and a 31-year-old woman, reported as Zeinab Ahmed, have been charged. Police allege Abbas went to Syria with her husband and children in 2014. Ahemd allegedly went to Syria with her family in the same year.

Police say the women were detained by........

© The Conversation