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 multiple DNA samples recovered during the investigation, including a partial profile found on a cigarette in a car.

North Yorkshire Police revealed yesterday that the 'familial DNA forensic investigation work' had included travelling the UK to try to obtain DNA from people, but had eventually concluded without a suspect being identified.

Martin Dales, friend and spokesman for Claudia's father Peter, said last night that Peter, family and friends shared the force's disappointment that the very detailed investigation had on this occasion proved inconclusive. 

"They are all appreciative of the continuing work by the police in trying to find Claudia but it is dependent on the quality of intelligence and information that comes to them from the public," he said.

"Someone knows something but the something is being withheld which after nearly 10 years is both wrong and cruel to Claudia’s family.”

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.

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

A force spokesman said yesterday that 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,” he said.

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

Detective Superintendent Dai Malyn, senior investigating officer in the case, 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.

“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 are 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 should phone 101.