A SEX offender is behind bars for preying on two schoolgirls in what a judge said was a campaign of "persistence".

Serena Ransom, 20, took advantage of the vulnerable teenagers and their attraction to her, Teesside Crown Court was told.

Ransom was found guilty of four offences after a trial but still denies doing anything wrong, Judge Peter Armstrong heard.

He family and her partner - who was prosecuted for witness intimidation - also refuse to believe the young accusers stories.

Prosecutor Shaun Dodds said she made sexual advances towards two underage girls, who cannot be named, between 2013 and 2015.

The first and youngest victim was “particularly vulnerable” when Ransom sexually assaulted her by giving her lovebites.

“She was simply too young for you to behave in that way,” Judge Armstrong told Ransom, of Bishopton Lane, Stockton.

She gave the second, older girl lovebites, kissed her on the lips and asked her to touch her intimately, said Mr Dodds.

The girl’s grandmother said in a victim impact statement that she changed from "loving" to "isolated and withdrawn".

She said the events left the youngster having trouble sleeping and frightened to leave the house without a family member.

Her school work was dramatically affected, she was unable to concentrate because of the court case and she failed GCSEs.

Ransom was convicted of sexual assault, inciting a child to engage in sexual activity and two charges of sexual activity with a child.

She was cleared on two other sexual assault counts and one count of inciting after a five-day trail last month.

Paul Reid, mitigating, said yesterday (Thursday, September 17): “I described her to the jury as a kid, and I stand by that assertion.

“She is very naive, very young, very inexperienced and quite clearly has her own problems.

“She’s spent five months in custody, the first time she’s ever been incarcerated. This is clearly somebody who needs assistance."

He told Judge Armstrong: “I’m afraid the defendant’s family have adopted an attitude towards this of complete denial.

“Your Honour saw these two girls, both of whom conceded that the activity was entirely consensual and made various remarks about their feelings towards Serena Ransom.”

Ransom was locked up for 18 months and was given a sexual harm prevention order banning her from work or unsupervised contact with under-16s, and she will be on the sex offenders’ register for ten years.