THE final lead being pursued by detectives investigating the suspected murder of Claudia Lawrence has come to nothing.

The one outstanding line of inquiry - which police hoped might shed light on what happened to the missing York chef - related to a partial DNA profile found on a cigarette in a car.

North Yorkshire Police said in January last year, as the force scaled down a £1 million review of the case, that the profiling was the only outstanding line of inquiry and it estimated it would take a further six weeks to finalise the matter.

However, the profiling work took far longer to process than originally anticipated.

In March, on the ninth anniversary of Claudia's disappearance, police said it was 'due for completion' and the force would publicly confirm this when it was in a position to do so.

Now the force has revealed that 'familial DNA forensic investigation work 'has been completed and concluded without identifying a possible suspect or suspects.

It said the task had taken longer than first anticipated due to the amount of research and analytical work undertaken by a small team when trying to identify people they required elimination DNA from as part of the familial DNA process.

"It has involved travelling around the UK to try and obtain DNA by consent from people who have similar DNA profiles to the unidentified samples recovered during the investigation," said a spokesman.

"There has also been work done to reconstruct Claudia’s DNA from various sources for elimination purposes."

Detective Superintendent Dai Malyn, the senior investigating officer in the case and Head of the Cleveland and North Yorkshire Major Investigation Team, said: “While these inquiries have been worthwhile and necessary to the investigation, they concluded without identifying a possible suspect or suspects from the DNA analysis.

“However, it demonstrates that we will continue to use forensic and other investigative work to progress this review.”

He added: “This is naturally very frustrating for the investigation team and our thoughts are very much with Claudia’s family who remain desperate for a breakthrough. The family have been updated about the completion of this work.

“As I have said before, the investigation will always remain open and we still receive information on a weekly basis that requires assessment and follow-up.

“People who have still yet to come forward who have visited Claudia’s house or been in her car for any reason, should still do so in the confidence that we can eliminate them against the outstanding DNA profiles.”

Anyone with information that could assist the investigation should contact North Yorkshire Police on 101, select option 1, and pass details to the Force Control Room quoting "Claudia Lawrence".

Alternatively, contact Crimestoppers anonymously on 0800 555 111 and quote “Claudia Lawrence, North Yorkshire Police”.

For more information about the Claudia Lawrence investigation, please go to the North Yorkshire Police website

Claudia was 35 when she was last seen in Heworth, where she lived, on March 18, 2009.

She was reported missing the following day after she failed to turn up for a shift at work at the University of York.

In 2013, North Yorkshire Police announced the Major Crime Unit was to review the investigation into her disappearance and forensic officers subsequently carried out a new search at her Heworth Road home which lasted several weeks.

Four men were later arrested on suspicion of her murder but the case against all four was dropped.

The force said last January the three-year probe had moved to a ‘reactive phase,’ which would review any new and compelling information that came to light.