By The AsiaOne Techbot

When 17-year-old Ashleigh Hall told her mother she was going to a friend's house to stay over for the night, she did not know that the person she was meeting is a known sex predator.

Hours later, the teenage girl was dead and her body thrown into a ditch near Sedgefield, a county in northeast England.

According to the English newspaper the Daily Mail, a 32-year-old man later told police that he was responsible for the killing.

He also said that he had posed as a 16-year-old boy on the social networking site Facebook and struck up a friendship with Ashleigh.

On Sunday (25 October), Ashleigh left home at about 7pm, telling her mother that she would be staying over at a friend's place and would be back the next afternoon.

When the teen failed to return, her mother tried calling her mobile phone repeatedly but there was no answer.

On Monday, police arrested a man at about 5.40pm for suspected traffic offences. The man later told officers that he had killed Ashleigh.

Further investigations revealed that the man was a registered sex offender, who had previous convictions for attacks on young women.

According to a police spokesman quoted by the Daily Mail, it was understood that the victim's family had since looked through her computer and discovered conversations the teen had with an unknown man.

Ashleigh, who was a studying childcare at Darlington college, was said to be a popular student, the Daily Mail reported.

A friend who spoke to the Daily Mail said that he "heard that she had been talking with a man on Facebook. He told her he was 16, but obviously it looks like that was a lie."

This is the second case in recent weeks to involve an adult posing as a younger person online in an attempt to initiate a relationship with a teenager.

Earlier, a US man was arrested for possession and distribution of child pornography, and was later found to have posed as a 16-year-old girl in order to obtain explicit photos from a 15-year-old female victim.

Online lover girl turns out to be old man
The 52-year-old US man posed as a 16-year-old girl and obtained explicit photos from female teenage victim.