THE mother of murdered schoolgirl Nikki Allan is facing fresh heartache after her sister was attacked by two people while walking home from a Christmas night out.

Sharon Henderson said the shocking incident has brought back memories of the day her seven-year-old was found dead in a derelict building in Sunderland, after being stabbed 37 times in 1992.

The 50-year-old's elder sister Joan Mann suffered injuries to her face in the early hours of Sunday morning after enjoying drinks at the Oddfellows Arms in Seaham, County Durham.

Grandmother Sharon said Joan, 53, only lives 150 yards from her home in the town but usually gets a taxi in a bid to stay safe.

She said: "I was phoned by a family member and straight away what happened to Nikki came flooding back. I could tell by the tone of voice that it was something serious.

"I felt sick and started to wonder if my sister had been murdered. I was so relieved when I was told she was alive, but the attack is horrifying. I could barely bring myself to look at the pictures of her injuries."

Sharon says Joan was attacked by two people shortly as she was walking home along Church Street.

She added: "I have been told she was jumped on by two people and stabbed. She was taken to the Sunderland Royal Hospital, but has been released now. I don't know if the attackers took anything."

A spokesman for Durham Constabulary said: "The incident was reported to us on Monday and enquiries are at an early stage.

"We would like to hear from anyone who has information regarding this alleged assault."

Sharon has launched a Facebook appeal in a bid to trace her sister's alleged attackers, in the same way she has done for her daughter, whose killer has never been found.

Seven-year-old Nikki vanished in October 1992 after leaving her grandparents' flat in Wear Garth, Sunderland.

Her body was found lying in a pool of blood inside the Exchange building.

In 1993, George Heron, who was 24 at the time, was charged and went on trial for murder at Leeds Crown Court, however he was acquitted by a jury.

In 2014, Northumbria Police arrested 47-year-old Steven Grieveson, who was already in prison for murdering four teenage boys, on suspicion of Nikki's murder.

He was questioned and bailed but he faces no further current action.