The police officer who attended the scene said: "I'll never get over what I saw there."

WARNING: This post contains explicit details about child sexual abuse and intergenerational incest. If you or someone you know has been a victim, we’d recommend you don’t read any further.

There’s a nine-year-old girl who doesn’t know how to use the toilet and a 12-year-old boy who doesn’t understand showering.

A 15-year-old boy  cannot talk in a way that can be understood, and his developmental ability is at that of a children still in kindergarten.

A 14-year-old boy has a severe intellectual disability. He has not grown properly; he is seriously underweight. He also cannot read nor write like a teenager should.

Then there’s the 14-year-old girl. She doesn’t know how to clean her teeth or use toilet paper, also can’t read and write and doesn’t even know how to run a brush through her own hair.

These are just some of the stories of the group of 40 adults and children who authorities recently discovered living in a valley just southwest of Sydney.

Most of the 12 children, aged between 5 and 16, were malnourished and showing signs of severely decayed teeth. Many can’t talk, and almost all of them can’t read or write, and most had probably never seen a doctor or gone to school.

NSW Police and Community Services discovered what was happening when in July 2012 they responded to reports from local residents that children living on the property weren’t attending school. One senior police officer said she would never get over what she saw.

The Colt family – a name they’ve been given by the courts to protect the identity of the children – were found living in a combination of caravans, sheds and tents.

The sheets they slept on were stained; probably never washed. There were even reports of a kangaroo asleep on one of the kid’s beds when police arrived on the scene.

There was no electricity running to the land, no running water and no kind of sewerage system.

And all of this has come about as a result of intergenerational incest, undertaken by a family who have moved from South Australia to Victoria, from Western Australia and now to NSW – presumably in an attempt to avoid authorities.

It’s been described as “one of the worst instances of child abuse seen in Australia”. And it’s only come to light in recent days after a NSW judge ruled that the children- many of whom have been born “oddly-formed features” and genetic conditions as a result of the lineage –  should be permanently taken away from their four mothers.

This from Fairfax:

The most shocking revelation came after the removal: of the 12 children removed, only one has parents who are not related. Genetic evidence demanded by the Children’s Court suggests their incestuous lifestyle may have been repeated over generations.

The incest may be one of the reasons for the family’s move to their secluded farm home. There are four mothers involved, three of whom are sisters: Rhonda, 47; Betty, 46; and Martha, 33. The fourth mother, Raylene, 30, is the oldest child of Betty, who has had 13 children.