A British police attempt to use DNA to identify a suspect in the case of missing chef Claudia Lawrence has failed.
Detectives traveled across the country trying to compare the sample of Miss Lawrence's car.
The then 35-year-old Yorkwoman Claudia disappeared on her way to work in March 2009. The officials believe that she was murdered.
The DNA sample was found on a cigarette in her car, which was in a garage that was repaired when she disappeared.
Police in North Yorkshire had hoped to find a "family DNA match" that would lead them to a suspect, but they've pulled a blank.
Despite extensive investigations and several arrests, no one was charged with their disappearance.
The case remained open, the troop said.
Martin Dales, a spokesperson for Miss Lawrence's father Peter, said the family and friends shared the disappointment of the police "that this very intense, lengthy, and nationwide DNA study has proved inconclusive on this occasion."
"They are all grateful for the continued work of the police in finding Claudia, but it depends on the quality of the information and information they receive from the public," he said.
"Someone knows something, but something is held back, which after almost ten years is wrong and cruel to Claudia's family."
Miss Lawrence from the Heworth area of York disappeared on her way to the University of York.
Her last known contact with someone was a call to her mother on March 18, 2009.
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She did not come to work the following day and was reported missing.
Det Supt Dai Malyn, who heads the investigation, said the team did not find the breakthrough they hoped for.
Malyn said, "Of course that is very frustrating for the investigation team, and our thoughts are very much with Claudia's family, who are desperate for a breakthrough.
"The family was informed about the completion of this work.
"As I said earlier, the investigation remains open and we continue to receive information on a weekly basis that requires assessment and follow-up."
The police said in January 2017 that the study of a DNA profile would take another six weeks.
The operation involved obtaining evidence through the consent of individuals who had similar DNA profiles to the samples not identified during the search.
Work has also been done to reconstruct Miss Lawrence's DNA for elimination purposes.
People who had visited Miss Lawrence's house or were in their car for whatever reason and had not come forward should contact the troop, she added.
Claudia Lawrence timeline
- March 18th, 2009 The final view of Miss Lawrence as she returns to her home after a shift at work and talks on the phone with her mother Joan
- March 19, 2009 The police are informed about their disappearance after not meeting a friend for a pre-arranged drink in a pub
- March 25, 2009 CCTV recordings of the chef's last known movements are published
- April 24, 2009 Detectives say they treat the disappearance of Miss Lawrence as a suspected murder investigation
- May 6, 2009 The police say they received more than 1,000 phone calls because of the disappearance and had accepted 1,096 statements
- May 6, 2010 Miss Lawrence's father Peter calls for an urgent independent investigation into the police investigation
- July 29, 2010 The police confirmed that they are reducing the number of officials responsible for the investigation
- October 29, 2013 Police announce that a new forensic search of Miss Lawrence's home is due to begin as a new review of the case
- May 13, 2014 A 59-year-old man is arrested on suspicion of murder. He will be released without charge later in November
- March-April 2015 Four men are arrested on suspicion of murder and released on bail
- March 8, 2016 The police say that the Criminal Investigation Department has decided that the four men will not be charged
- January 17, 2017 The police say the review of the case, which cost 1 million pounds, will be "downsized."
- November 8, 2018 Police can not identify "a potential suspect" after DNA analysis