Explainer: Everything we know about the Blue Mountains circus school child abuse.

A group of NSW circus school workers have been arrested after police discovered they had been sexually and physically abusing three young boys over a two-year period.

It’s news that’s no doubt terrified many parents whose kids have may have attended the school.

Here are some important questions answered:

Who are the alleged perpetrators and who are their victims?

Seven people have been arrested – four women, two men and a 17-year-old girl, all of whom are in custody facing a total of 127 charges relating to sexual abuse, physical torture and creating child abuse material.

All of the alleged perpetrators – ranging in age from 58 to 17 – live in the Blue Mountains area and have connections to The Arcade Circus, a Katoomba-based business that catered to children, some with disabilities. It’s believed one of the women who’s been charged is the owner of the circus training school.

Police have said the three boys the group allegedly abused were all under the age of eight and were known to the circus but not students at the school, ABC reports.

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What charges do they face?

The alleged abuse occurred between 2014 and 2016 in the Blue Mountains.

A 58-year-old woman faces 43 charges, including aggravated kidnapping. It is believed she is the owner of the circus school.

She, along with a 26-year-old woman, a 29-year woman, 17-year-old girl and 52-year-old man, 20-year old woman and 18-year-old man were charged with aggravated sex assault and/or sexual assault of a child under the age of 10.

Members of the group allegedly performed sadistic sex acts on the boys as well as “blood rituals” where blood was taken from the boys and they were forced to drink it, the ABC reports.

These and other acts of abuse were filmed and photographed and used to create child abuse material.

How were they caught?

Last year, NSW Police learned of reports of the sexual abuse of three boys and in July detectives from the Child Abuse and Sex Crimes Squad established Strike Force Baillieu to investigate.

Those investigations led them to arrest the seven people in their homes in Katoomba, Canterbury and Wentworthville on Monday.

All seven were refused bail on Tuesday.

-With AAP