A fresh Crimewatch appeal is to be made to try to solve the murder of a seven-year-old-girl who was stabbed 37 times more than 20 years ago.
Schoolgirl Nikki Allan was killed just yards from her home in Sunderland in 1992 and her body dumped in a derelict warehouse.
But no-one has ever been convicted of the murder and Northumbria Police hope that appearing on the BBC1 show may uncover new clues.
Detective Superintendent Roger Ford, who leads the force's Major Crime Teams, will appear on the show along with a reconstruction of Nikki's death.
Nikki was found dead on October 7, 1992, in the then-derelict Old Exchange Building, near to her family home at Wear Garth, Sunderland.
A number of people were arrested in connection with the investigation but no one was convicted.
Detective Superintendent Ford said: "This was an extremely brutal attack on a defenceless seven-year-old girl and 21 years after it happened it's still talked about in Sunderland and the local area.
"Nikki's family have been left devastated by what happened and we will never give up trying to find her killer.
"Technology and forensic investigation techniques are improving all of the time and it's our hope that these advances along with new information from the public could lead to us finding out who murdered her.
"We want the Crimewatch reconstruction to reach as many people as possible in the hope it jogs someone's memory, especially people who may be from Sunderland and have moved away over the years since the murder.
"We want to appeal directly to anyone who used the Old Exchange Building back in 1992. The building was a large, dark and derelict building, however we know it was used by drug takers, vagrants and local youths as somewhere to hide out.
"Lots of people used to come and go from the building and we want anyone who used to spend time there, for whatever reason, to ring us and talk to us about what they remember about the place - especially the names and details of anyone who they know visited or spent time there."
Nikki's mum Sharon Henderson, 48, who will also appear on the show, has spoken of her hopes that a fresh appeal could finally bring an end to her two decades of heartache.
Sharon, of Ryhope, Sunderland, told her local paper: "I want to see the killer behind bars. I have never given up hope that justice will be done. I have fought for so long and I know Nikki would be proud of me."
• The Crimewatch show will be broadcast on BBC1 at 9pm this evening. Anyone with any information into the murder of Nikki Allan can speak to detectives on a dedicated number, which is 0800 4565 914, or by ringing Crimestoppers anonymously on 0800 555 111.