A MAN 'exploited' a vulnerable 15-year-old girl for sexual purposes, it was alleged in court.

Steven Dex Kerley, 25, took advantage of the girl who was difficult to control and suffered from Asperger's Syndrome and attention deficit hyperactivity disorder.

Prosecutor Peter Hampton said her vulnerability was 'in essence manipulated by the defendant'.

A Sheffield Crown Court jury was told the teenager believed she was in a normal, mature relationship with the defendant and was not supporting his prosecution.

Kerley, of Cemetery Road, Grimethorpe, denies one offence of sexual activity with an underage girl between January 25 and February 2.

Mr Hampton said her parents were struggling to control the girl's behaviour last September and would call out the police when she went missing.

She started staying out against their wishes and began seeing a man whom the prosecution say is Kerley.

Kerley was issued with a child abduction warning notice by the police stating the girl's age and that her parents did not give permission for him to be with her.

But despite the warning, Kerley continued to see the girl, said Mr Hampton.

Matters worsened until Kerley's car, with the girl in the front passenger seat, was involved in a crash with another car near South Kirkby on February 13.

The girl walked quickly away and Kerley was seen to wipe down the doors and throw items into a hedge.

"It was an attempt to get rid of any DNA which could be linked to the girl on the inside of the vehicle," said Mr Hampton.

The girl needed treatment at Barnsley Hospital for a cut to her head but denied being with Kerley, saying she had fallen off a fence in a park.

Kerley was later arrested on suspicion of child abduction and scientists were able to match the girl's DNA to an airbag which inflated in the crash. Knickers seized from her bedroom also showed Kerley had participated in some form of sexual activity with the teenager.

Kerley admitted child abduction over the car incident but maintained he thought she was 17. He denies sexual touching.

He claimed she had pursued him after he was given the warning notice by police.

The trial continues.