A man has been arrested on Teesside over the murder of a schoolgirl in one of Britain's most notorious unsolved child murders.

Northumbria Police detained the man, said to be in his fifties, in Stockton on suspicion of murdering Nikki Allan following a raid on a house in the town.

The force said the arrest on Tuesday was connected to a 'historic offence'.

And it confirmed on Friday that a man was held over the death of the seven-year-old, who was found stabbed to death in a derelict building after vanishing from near her Sunderland home in 1992.

Northumbria Police detained a man in Stockton on suspicion of murdering seven-year-old Nikki Allan (pictured) following a raid on a house in the town. The schoolgirl was found lying in a pool of blood with 37 stab wounds to her chest in 1992

Nikki vanished on a Wednesday evening more than 25 years ago, after leaving her grandparents' flat in Sunderland's Wear Garth. Right, her mother, Sharon Henderson (last year when she joined forces with Northumbria Police to mark 25 years since her daughter's murder)

Nikki had been left lying in a pool of blood with 37 stab wounds to her chest.

Detectives had confirmed in October they had made a DNA breakthrough in the unsolved child killing case.

The force said in a statement: 'A man was arrested on suspicion of murdering schoolgirl Nikki Allan. He has been released under investigation. Enquiries are ongoing.'

Witnesses said forensic officers in white suits spent around eight hours coming in and out of a house on Tuesday morning.

Neighbours saw officers turn up around 8am. A man was led away and the house was searched for a number of hours.

Nikki's body was found in the derelict Exchange building after her shoes were spotted outside. Above, floral tributes at the scene in 1992

Officers were said to have brought out numerous clear plastic bags, filled with items.

At around 3pm, forensic officers left the scene and more police turned up.

Nikki's tearful mum Sharon Henderson, 51, said: 'It's been a very emotional time. When the police told me they had arrested someone for Nikki's murder it was such a shock I almost collapsed.

'Now he's been released I don't know what to think.'

One neighbour said: 'It was a big police operation, I've never seen anything like it.

'There were about 25 officers in forensic suits going through the place. They took away his computer stack, had the carpets up and bagged up two massive sacks of evidence.

'They went through the house, his loft, the bins and back yard and were there on Tuesday from 8am to 3pm.'

Cleveland Police said that a neighbouring force was leading the investigation.

Nikki vanished on a Wednesday evening more than 25 years ago, after leaving her grandparents' flat in Sunderland's Wear Garth.

Nikki, her mother and their family were well known at the Wear Garth flats, which have since been pulled down.

Breaking his silence about his daughter's death last year, Nikki's father David Allan said: 'I have remained quiet about Nikki's death for 25 years but now is the time I need to speak out'

Neighbours formed search parties in a desperate bid to find the little girl.

But her body was found in the derelict Exchange building a few hundred yards away, after her shoes were spotted outside.

Breaking his silence about his daughter's death last year, Nikki's father David Allan said: 'I have remained quiet about Nikki's death for 25 years but now is the time I need to speak out.

'I can't begin to describe how difficult life has been without my beautiful little girl. I would never want anyone to suffer the heartache we have suffered as parents.'

In 1993, George Heron, 24 at the time, stood trial for Nikki's murder, but was cleared by a jury at Leeds Crown Court.

Then in 2014, Sunderland serial killer Steven Grieveson was arrested and questioned on suspicion of Nikki's murder. But he was later told he would face no action.

The charity Crimestoppers had offered a reward of up to £10,000 for anyone who has information which leads to the conviction of Nikki's killer.

Anyone with any information about Nikki's death can speak to Northumbria Police's major crime team on 101 ext 69191 or the independent charity Crimestoppers on 0800 555 111.