Advances in DNA technology helped to pinpoint the killer of Nikki Boyd, who probably thought he had escaped justice for his horrendous crime, committed in 1992.

During the course of his trial over the last three weeks at Newcastle Crown Court, the jury was told David Boyd was not a suspect in the immediate investigation into the killing of Nikki.

This was despite being a neighbour and coming forward weeks later to reveal, in a witness statement to police, that he was probably the last man, other than her killer, to have seen her alive in the night she disappeared, on October 7, 1992.

He told investigators he had seen Nikki playing below as he glanced from the balcony of his second-floor flat at Wear Garth, at about 9.30pm that night.

Read more: Jury finds David Boyd guilty of killing Nikki Allan in Sunderland

It was thought that about 15 minutes later she was lured away from the area outside the Boar’s Head pub, opposite Wear Garth, and by 10pm she had been killed in the derelict Old Exchange Building, on Low Street.

By the time Boyd gave that statement, he was safe in the knowledge that police had arrested and charged another neighbour, George Heron, with Nikki’s murder.

Mr Heron was cleared on the judge’s directions the following year at his trial at Leeds Crown Court.

As the case remained unsolved it was said to be the, “incredible perseverance and determination” of Nikki’s mother, Sharon Henderson, which helped to persuade Northumbria Police’s then Chief Constable, Steve Ashman, to take a further look at the case, in 2016.

Ms Henderson had launched a petition to have the case reopened and met Mr Ashman, who agreed to the re-inquiry.

By 2017, there had been a breakthrough in forensic investigation capabilities with Y-DNA testing, allowing identifications to be made by matches with male bloodlines only.

The “cold case” team, headed by lead detective Lisa Theaker, a now senior officer with Cleveland Police, looked at all those who had featured in the original investigation.

Among them was Boyd, who was known as either ‘Smith’ or ‘Bell, in 1992.

He was one of 2,221 people investigated by the new inquiry team and was asked to give a DNA sample, when he was visited at his home in Norton, Stockton, in October 2017.

Weeks later a match was found with his DNA profile emerging on four areas of the clothing worn by Nikki on the night of her disappearance and death.

It led to an investigation of his background and movements prior to and post-Nikki’s murder, leading to his arrest in April 2018.

Following his initial interviews, he was released, “under investigation” as police turned their attention to all those others who featured in the original inquiry.

Read more: Nikki Allan trial judge clears gallery after commotion upon verdict

All 839 remaining men were visited, 641 of them in Sunderland, and each was eliminated, including the original suspect, George Heron, leaving only one probability in the inquiry team’s minds, that Boyd was, “their man”.

Following today’s verdict their hard work, and persistence, backed by scientific advances, has helped to finally catch the real killer of Nikki.

Detective Chief Superintendent Theaker, the senior investigating officer in the case, said today: “Nikki would have been 37 now and who knows what her life could have been.

“But her future was cruelly taken away her by David Boyd.

“The pain and suffering that he has caused, and to so many people, is immeasurable.

“This is a huge day for Nikki’s family. I would like to thank them for their incredible strength.

“After 30 years, they have justice.

“Since 2017, as an investigative team, we have worked tirelessly on what has been a complex and challenging case.

“Our commitment has always been to find the person responsible and ensure they were brought to justice.

“New forensic techniques were a key part in this investigation, and we have been supported by incredible experts, witnesses and specialists who have helped us discover and prove who was responsible.”

Read next:

* Timeline of events leading to David Boyd's conviction for murder

* Key events leading to conviction of David Boyd for murder of Nikki Allan, seven

* Sharon Henderson's fight for justice to find Nikki's killer David Boyd

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Det Ch Supt Theaker added: “The residents of Sunderland have also played their part in achieving justice for Nikki and her family.

“I want to take this opportunity to thank each person who assisted our investigation and provided their DNA for elimination.”

Boyd, 55, of Chesterton court, Norton, was remanded back into custody after today's verdict and he will be sentenced at the court, in a possibly televised hearing, on Tuesday May 23.