Paedophile brothers Adam Riley and his brother Ian both lived within the grounds of a Burgess Hill primary school.

Caretaker Adam had sex with underage girls and made inappropriate phone calls to children.

He was caught after child protection specialists CEOP traced his brother, who shared photos on the world’s largest paedophile network loverboy.net.

When detectives from Sussex Police’s Paedophile Online Investigation Team (Polit) started investigating Ian, they uncovered the depraved world the siblings lived in within the grounds of a school.

Karate instructor Ian Riley secretly filmed his pupils using a camera hidden in a spy pen and was jailed for three and a half years for making and possessing indecent images of children.

His brother had sex with a 15-yearold girl, sexually assaulted another woman, abused his position to get phone numbers for children and made calls to sex chat lines from the school office.

Detective Constable Chris Smith, of Sussex Police, said: “Adam Riley and Ian Riley are brothers, but their two cases are not linked to each other.

“Ian Riley’s offences were Internet based and his brother’s were contact based.”

Ian Riley was yesterday linked to the world’s largest paedophile network, smashed by CEOP investigators.

Police were then led to his depraved brother, Adam.

Adam Riley initially denied sexual assault and indecent exposure, but changed his plea once the trial started. Richard Barton, prosecuting, told Hove Crown Court Adam Riley had admitted a “gross breach of trust” by having sex with a 15-yearold girl when he was 23.

Mr Barton said that Riley had also made disturbing anonymous phone calls to the friends of a woman who he was in a relationship with in 2007.

In 2008 police were told about calls made to premium rate sex chat lines from a phone at the school. After his arrest another woman reported being sexually assaulted by him earlier that year.

Mr Barton said: “Throughout his adult life Riley has obsessively sexually harassed women, particularly young women. His conduct has escalated from silent phone calls to sexual assault and extreme deviant sexual behaviour.”

Adam Riley will be sentenced on May 19.