This evil killer was well known to police. He had previously been jailed for raping two teenage prostitutes and investigated by detectives in connection with at least five other serious offences.
Ashleigh Hall was a typical messy teenager who fell victim to Peter Chapman's manipulative and cunning lies.
It was on the social networking site Facebook that Miss Hall's killer convinced her he was a handsome young man interested in getting to know her, and then pretended to be the boy's father to lure her into his car where he raped and murdered her.
Miss Hall lived with her mother and helped to raise her three younger sisters. Friends said she had been "giddy" with excitement about meeting 19-year-old Peter.
But Chapman was far from the attractive image he portrayed on the online sites he used. Balding and slightly-built, he looked much older than his years.
He made his intentions clear from the beginning of the six days he was in contact with Miss Hall before her death. He failed to turn up for their first meeting, aware that she would never believe he was the attractive young man in the pictures.
But he had a plan. Two days later, masquerading as Peter Cartwright, he arranged for Miss Hall to be picked up by a man he said would be his father. Chapman would be driving the car.
Miss Hall was taken in by the trap. Before he arrived at her home on the evening of October 25, the killer had texted his victim saying: "Hi hun its pete's dad are you sure you don't mind me picking you up? Pete is really looking forward to seeing you and yes its ok for you to stay."
A few seconds later, she replied: "No its fine I dnt mind I trust him so I trust u and thank u." Chapman sent another text message, pretending to be Peter, which said: "Me dad's on his way babe he says excuse the state of him lol (laugh out loud)... he doesn't have to come in and meet your mum does he lol he'll be a mess probably lol oh and are you wearin some sexy underwear for me hehe x." She replied: "Okaii babe and no he doesn't lol and its okaii haha, wat car has he got and u will have to wait and see wnt u ;) x x."
Chapman drove the teenager to an area off the A177 at a lay-by at Thorpe Larches, near Sedgefield. Here the terrified youngster was forced to perform oral sex on her attacker and then raped. The prosecution described how he removed her lower clothing and gagged her with duct tape which he wound around her face and arms. At one point he removed the bindings from her arms to allow her to pull up her clothing but then re-tied her, winding yet more tape over her face which suffocated her. He dumped her body in a farmer's field.
The following day, as Miss Hall's mother became increasingly frantic at her daughter's whereabouts, Chapman's car was stopped by police for a routine motoring offence.
Despite the fact that police had no idea that Miss Hall had been murdered, Chapman confessed to astonished officers that he had killed her.
Miss Hall's mother learned of her daughter's death on the 30th time she rang her mobile phone after her disappearance. It was answered by a police officer.
Yesterday, after weeping though the evidence at Teeside Crown Court, Andrea Hall (39) described the former Girl Guide as a friend as well as a daughter. She said she had been powerless to stop her daughter going out on the night she met Chapman.
"You tell them to be careful but she said she was meeting a 15, 16, 17-year-old or whatever age he said he was. So of course she was going to meet him. He was a nice looking boy. I couldn't have stopped it and I wouldn't have stopped it," she said.