A former detective who worked on the investigation into the murder of a girl 15-years ago says someone in the community knows who killed her.
The 16-year-old was stabbed more than 40 times in a random killing
Claire Tiltman, 16, was murdered in an alleyway in Greenhithe on 18 January 1993, while on her way to see a friend.
Nobody has been charged with her murder but her parents are still hoping Kent Police will find her killer.
On the anniversary of her death retired Det Supt Nick Biddis urged people with information to come forward.
Mr Biddis said: "There is somebody in that area, in the Greenhithe area, who knows something even now that happened 15 years ago, that should come forward.
"I would plead with them really... lets give Lin and Cliff proper closure and the rest of the community because it is still having an effect."
Mr Biddis said the killer would have had a good local knowledge.
He added: "In my understanding there are people in that area, that still live in that area, that probably have the answer."
Claire, a pupil at Dartford Grammar School for Girls, was stabbed more than 40 times, in an apparently motiveless attack four days after her 16th birthday.
She was an only child and her parents Cliff and Lin still receive Christmas cards from her former schoolmates and teachers.
A Kent Police spokeswoman said: "The case was passed to the case review team three years ago. It is constantly reviewed and monitored.
"It is not closed and any new information will always be investigated."
A memorial plaque to Claire was mounted on a wall on London Road in Greenhithe - the road leading to the alleyway where she was murdered.
Another plaque is on a bench in a memorial garden 100 yards from her parents' home, while a road on a new retail development in Greenhithe was named Claire Causeway in her memory in 2002.