Michaela Murch, 18, has been found guilty of sexually assaulting a vulnerable boy with a toilet brush

Two teenagers have been found guilty of sexually assaulting a vulnerable boy with a toilet brush at a children's hospital during a 36-hour attack.

The 15-year-old boy was 'stripped, beaten, strangled, kicked and burned' by 18-year-old Michaela Murch and her accomplice during the prolonged ordeal.

They put cigarettes out on his feet, tried to suffocate him with a plastic bag and forced him to run naked through the centre of a busy shopping centre.

And while he was being treated in hospital for burns they inflicted to his legs and feet, he was indecently assaulted in the toilet with a brush.

Murch, 18, and an accomplice who cannot be named for legal reasons, denied sexually assaulting the boy but were both convicted after a trial.

They face sentencing at Bristol Crown Court next year.

Opening the case earlier this month, prosecutor Richard Posner said: 'Michaela and her co-defendant are accused of embarking on a course of conduct that was intended to harm their victim, a 15-year-old boy.

'His vulnerability allowed them to manipulate a trust he had placed in them, and make him the subject of a degrading and intentionally humiliating attack.

'Both have pleaded guilty to a number of different offences where they hurt the victim. They acted together when doing what they did.'

The 36-hour ordeal started on April 10, after the boy visited St Michael's Hospital near Bristol city centre.

The victim was taken to St Michael's Hospital in Bristol following the initial attack but while he was there Murch and her accomplice assaulted him with the brush

After leaving the premises, the boy claims he was forced to remove his clothes and run in the street naked.

CCTV footage shown to the jury captured the boy running naked towards the main shopping centre flanked by the two defendants.

When a concerned passer by stepped in and reported the incident to the police, the trio walked on to a local park.

There the two burnt the boy's leg using a lighter and put cigarettes out on his feet.

The boy said he was then led to the nearby Galleries shopping centre where a plastic bag was placed over his head in an attempt to suffocate him.

Murch and her co-defendant had previously pleaded guilty to putting a person in fear of violence, two counts of assault occasioning actual bodily harm and two counts of assault by beating.

The teenager denied sexually assaulting the boy with the toilet brush and claimed it was Murch who had carried out the act.

She told defence lawyer William Rose they were 'sorry' for those offences.

The Recorder of Bristol His Honour Judge Peter Blair QC adjourned sentencing, pending reports, to January 8.

Murch was remanded in custody.