A group of high school 'mean girls' have admitted to targeting and falsely accusing a boy of sexual assault because they 'just don't like him'.

A 26-page federal lawsuit was filed in Pittsburgh, Pennsylvania, on the eve of October 3 - also known as Mean Girls Day in tribute to the 2004 cult classic - against a clique of five girls at Seneca Valley High School.

The boy's parents describe the clique as 'mean girls' who 'conspired in person and via electronic communication devices to falsely accuse [their son] of sexual assault on two occasions.'

Their son, referred to in the lawsuit as TF, was fired from his job at a local pool, forced to serve time in a juvenile detention facility, is now home-schooled and suffers psychological trauma after the teenage girls bullied him and later admitted to lying about their sexual assault claims.

A clique of five 'mean girls' falsely accused a teenage boy of sexual assault. Mean Girls is a 2004 cult classic

The parents claim their son experienced 'gender bias' by school officials who 'did not take any action against the females involved' after the consistent bullying was reported.

'(TF) was basically being tortured in school by the other students and investigators, but the administration was only focused on protecting the girls who were lying,' the family's attorney Craig Fishman said.

'Once the allegations were proven false, they really didn't care one bit about TF and there has been absolutely no repercussions against the girls.'

His parents are now seeking unspecified civil damages against the girls' parents, the school district and the Butler County District Attorney's office.

The lawsuit, obtained by Trib Live, claims the first allegation came in July 2017 at a swimming pool where TF worked as a lifeguard.

A teenage girl, referred to as KS, accused TF of sexually assaulting her at the pool and he was fired from his life guarding job.

A former Seneca Valley High School female student who is friends with KS supported her claims.

TF was later charged in juvenile court with indecent assault and two counts of harassment. He pleaded not guilty, was put on probation and required to stay out of trouble for six months.

In a recorded interview with school officials, the lawsuit claims KS said she accused TF of sexual assault because 'I just don't like him'.

'I just don't like to hear him talk. I don't like to look at him,' KS reportedly said in the recorded interview which was obtained by Fishman.

The boy's parents are suing the 'mean girls' and Seneca Valley High School in Pennsylvania for damages

Then in October 2017, KS allegedly told her classmates she would 'do anything to get TF expelled', prompting other students to bully him by placing a tape with the word 'PREDATOR' written on his back during choir practice.

In March, a female friend of KS, identified as CS, told a school counselor that the teenage boy had walked into her home and sexually assaulted her.

Those allegations were supported by two other girls identified as ES and HR, accoridng to the lawsuit.

The teen was charged with indecent assault, criminal trespass and simple assault in April.

'On April 10, TF was removed from class at Seneca Valley High School and placed in leg and wrist shackles by the Jackson Township Police with the assistance of Juvenile Probation Officer Michael Trego,' the lawsuit stated.

Trego testified that the teen was a threat to the community and he subsequently spent nine days in a detention center before being sent home on house arrest.

But in May 2018, three of the female witnesses admitted they had lied about TF.

The District Attorney's Office ordered the charges be dropped against the teenage boy in late August in light of the girls' admission, but the lawsuit claims it has yet to do so.

'The Butler County District Attorney's office promised to file a petition to expunge the record of TF in September, but has not yet done so, providing further evidence of gender-based discrimination,' the lawsuit states.

It further claims that the district attorney has refused to file criminal charges against the five girls due to 'gender-based discrimination'.

'T.F. has had psychological trauma because of all this. He's had to see a psychologist to deal with the physical symptoms which are the direct result of being accused of something when he did not do anything wrong,' Fishman said.

The lawsuit states the school has also repeatedly refused to mark the girls' academic records for lying.