A north Norfolk woman has made a brave plea for information in a desperate plea to catch her daughter's killer on the 20th anniversary of the death.

Today marks 20 years to the day since the body of Natalie Pearman was discovered at Ringland Hills on the outskirts of Norwich.

The 16-year-old was a prostitute who had been working in the city's red light district and was last seen in Rouen Road a few hours before her body was discovered by a lorry driver in a layby at Ringland Road at 3.50am on November 20 1992.

A post mortem examination later revealed that Natalie had died from asphyxia with forensic swabs showing semen present in her body and on her underwear.

At the time of the initial investigation a DNA crime stain was obtained and loaded onto the national DNA database.

The subsequent investigation has seen more than 4000 people interviewed and samples of DNA taken from a large number of men, but yet the killer still remains undetected.

And now, ahead of this landmark anniversary, Natalie's devastated mother Lin has bravely decided to speak out to help try and finally get justice for her daughter.

Lin, 67, a mother-of-five, grandmother-of-two and step grandmother-of-two, said; 'I want justice for my daughter. She was 16, she was trying to earn a living the only way she could manage and age didn't want to be dependent on the state. She was trying to do her best to survive life, she didn't deserve what happened to her.'

Lin, who lives in north Norfolk, said she hopes the anniversary will help her in her quest for justice and the truth.

She said: 'I hope whoever feels they have a responsibility to others is going to feel guilty and forget about them and come forward - that's what I've been hoping all these years.

'It just gets worse. They say time heals and it does to a certain extent, but you have to learn to live with what's happened.

'The name means nothing to me - what I need to know more than anything else is why she was killed. I just want to know why, that's the hardest thing. Had she some knowledge that they didn't want getting out? She certainly said nothing to me.'

Lin, who has battled ill health in recent years, thanked her family and the police for their support, and pleaded with those with information to come forward.

Natalie's case is one of a number of investigations being looked at by Norfolk Constabulary's cold case team, set up in August 2008 to investigate murders, missing people and serious sexual offences which are still unresolved.

Detective Chief Inspector Andy Guy, who leads the cold case team within the Major Investigation Team, said he hoped the anniversary would be a turning point in the hunt for Natalie's killer.

He said: 'I've always felt there are people who are out there who know what went on or who were suspicious of something which went on and the 20th anniversary is an opportunity to ask those for whatever information they may have.

'Quite clearly whoever was responsible has arrived home in the early hours of 20 November 20 years ago and I'm sure someone must've noticed something odd about them - they got rid if their car or behaved strangely at the time.'

He added: 'For us it's really simple, we just ask for a name. We have the DNA of the person we want to speak to, it's just a matter of matching them up.'

Det Ch Insp Guy said you would expect someone who has demonstrated 'this level of violence' to have shown up on the DNA database before, but admitted the person could have been abroad, in prison or gave just missed out on when profiling came in.

Natalie was last seen alive in Norwich's Rouen Road at 1.15am. On the same day her body was discovered five miles away.

An appeal run by in the EDP, sister paper of the North Norfolk News, last year, generated a number of new calls, including one about a sighting of Natalie getting into a car on King Street on the night she disappeared.

The person has not got back in touch since despite police appeals for the person to come back to them.

Det Chf Insp Guy said: 'If there's something that's bothered you, if you've rung police before and haven't had the service you expect then please ring again and we will follow that up.

'In all our cold cases if you give us the information we will follow it up. It might be that people don't want to speak to the police and I understand that, but there's Crimestoppers and information can be given to them.'

Crimestoppers last year offered a �4,000 reward for information leading to the arrest and conviction of the killer in this case. The reward is still available.

Det Ch Insp Guy urged anyone with information, no matter how seemingly insignificant, to get in touch and help bring closure - and end the suffering - for Lin and the rest of Natalie's family.

He said: 'I think it's worth remembering that Natalie Pearman was only 16 years old when she died - she was nothing more than a kid.'

Anyone with information regarding Natalie's death is asked to contact the MIT cold case team on 01953 424520 or 101. Alternatively call Crimestoppers anonymously on 0800 555 111.

To view the cold cases log onto the website www.norfolk.police.uk, click on news and events and then cold cases.