Claudia Lawrence disappearance: New clues found in home and car
Detectives searching for missing York chef Claudia Lawrence say they have new lines of inquiry but no prime suspect.
North Yorkshire Police say her mobile phone was deliberately turned off on the day after she disappeared in 2009.
Unidentified fingerprints have been found in her house and a man's DNA found on a cigarette end in her car.
Detectives have said they think she was murdered and an appeal is to be shown on Crimewatch on Wednesday evening.
North Yorkshire Police's new major crime unit has been assessing the case and carried out new forensic work and searches at her home on Heworth Road.
Police said they found the additional fingerprints using "advanced techniques" not available in 2009.
Det Supt Dai Malyn, head of the unit, said: "We are keen to eliminate people who have been inside Claudia's home before and after her disappearance."
The detective said Miss Lawrence's hair straighteners appeared to be missing from her home.
"From our inquiries, it is doubtful that she would take them to work in her blue and grey Karrimor bag, which has also never been found," he said.
The investigation team still believe Claudia's silver Samsung D900 mobile phone was deliberately turned off by someone at about 12:10 GMT on Thursday, 19 March 2009.
Mr Malyn added: "Further analysis of Claudia's mobile phone, particularly cell site activity, also shows she was in the Acomb area of York in the weeks leading up to her disappearance.
"We believe she may have been socialising with a person or persons.
"If this is something a person wants to discuss with us sensitively, we can deal with that in a discreet manner using trained officers."
Mr Malyn said another new strand of the inquiry was focused on tracing a man who told staff in a Co-op store at Tang Hall in York that he knew Miss Lawrence or used to work with her.
This was on 1 April 2009, about 10 days after she was reported missing, said Mr Malyn.
The detective also said a DNA profile of a man had been established from a cigarette end found in Miss Lawrence's "green-blue" Vauxhall Corsa, which was being repaired at a local garage at the time she disappeared.
Mr Malyn said the DNA profile did not relate to any man who had yet come forward.
He added it was reasonable to consider whether there was a link between this man and an individual spotted by a witness known throughout the five-year investigation as the "left-handed smoker".
This man was seen smoking with a woman on Melrosegate Bridge in York at about 05:35 GMT on 19 March 2009, when Miss Lawrence would have been walking to work.
Mr Malyn said neither the man or the woman had been traced despite repeated appeals.
"It is vital that we trace this man as soon as possible as he could have important information to assist the investigation," he said.
Det Ch Supt Simon Mason said there was no prime suspect, but a "number of individuals" of "particular interest" to the investigation.
North Yorkshire Police will make a fresh appeal for information and detail the progress of the renewed investigation on BBC One at 21:30 GMT.