A predator on the Sex Offenders' Register killed a 17-year-old girl he met and groomed on Facebook after luring her to a secret meeting.
The 32-year-old posed as a 16-year-old boy to befriend Ashleigh Hall on the social networking site. [Girl, 17, murdered....see more here...]
But within hours of their first meeting, the teenager was dead.
The man is said to have bound and gagged her, and thrown her into the back of his car. Hours later he dumped her body in a ditch by a country lane.
Last night he was being quizzed on suspicion of murder.
At the police station he dramatically confessed: 'I've killed a girl', before leading them to the body.
The killing raises serious questions over how effectively the known sex offender was being monitored.
As a registered sex attacker he was required to inform police of any change of address.
Checks carried out after his arrest, however, revealed he had moved from his registered home without notifying the authorities.
Ashleigh, who was studying childcare at Darlington College, left her house at 7pm on Sunday, telling her mother she was going to stay at a friend's house and would be back the following afternoon.
When she failed to return her mother repeatedly rang her mobile phone but there was no reply.
On Monday evening at 5.40pm, traffic officers, alerted by their onboard computer, pulled over a Ford Mondeo being driven without any insurance on the A177 in County Durham.
They arrested the driver on suspicion of motoring offences and took him to Middlesbrough police station. He was then booked in and taken to a cell.
He told a custody officer: 'I want to tell you something, I want to speak to a detective.'
The man then told officers that he had killed a girl. He claimed she had suffocated after he gagged her and insisted it was an accident.
He offered to take them to the lane where he had dumped her body in Sedgefield
He took them to the place where he said he had flung the body on a road known locally as lovers' lane. Ashleigh's body was discovered at around 10.30pm.
After the body was found the man was taken to Darlington Police station where he underwent a medical examination, though detectives would not reveal if he had sustained any injuries either before, during or after the girl's death.
Nor would they confirm how the girl had died or whether she had been sexually assaulted.
The man gave detectives two names - one believed to be an alias - but officers are convinced they know who he is and have taken his fingerprints to establish his identity beyond doubt.
The man, who had a shaved head, is believed to have links with Merseyside and Stockton-on-
Police sources said he had previous convictions for sex attacks on young women and was a registered sex offender.
It is not known, however, if he was being monitored by Multi Agency Public Protection Arrangements, an agency set up to keep a close eye on dangerous sex offenders.
