The Crown Prosecution Service will consider bringing charges against four men arrested on suspicion of murdering missing Claudia Lawrence, police have said.
The university chef disappeared on her way to work in York in March 2009 and no sign of her has been found since, the Press Association reports.
The four men, in their 50s and from the York area, were arrested earlier this year and were currently on bail, North Yorkshire Police said.
Claudia Lawrence has not been seen since 2009
A file of evidence will be handed to the CPS once it is prepared, and assessment by lawyers of the case will take some time, the force said.
The officer in charge of the inquiry stressed it remained active and urged people not to identify the men in question.
SEE ALSO:
Detective Superintendent Dai Malyn said: "This is to ensure the investigation and legal process are not compromised or potentially damaged in any way.
"This includes naming or publishing images of the men, their home addresses, places of work, their vehicles and properties on traditional media platforms or social networking sites.
Miss Lawrence with her father Peter
"Your co-operation and support is greatly appreciated by the investigation team."
Anyone with information that could assist the investigation should contact North Yorkshire Police on 101.
Missing chef Claudia Lawrence
Missing chef(01 of46)
Undated North Yorkshire Police handout photo of Claudia Lawrence. (credit:PA)
Missing chef(02 of46)
Undated North Yorkshire Police handout photo of Claudia Lawrence. (credit:PA)
Missing chef(03 of46)
Undated North Yorkshire Police handout of Claudia Lawrence with her father Peter, as police investigating the disappearance of the university chef were today searching a run-down property near her home. (credit:PA)
Missing chef(04 of46)
Undated North Yorkshire Police handout picture of Claudia Lawrence (right), who is believed to have gone missing as she walked to work in York, pictured with her friend Jen King (left). (credit:PA)
Missing chef(05 of46)
Undated North Yorkshire Police handout picture of Claudia Lawrence (left), who is believed to have gone missing as she walked to work in York, pictured with friends Simon Foreman and Suzy Cooper. (credit:PA)
Rights for families of missing people(06 of46)
Peter Lawrence, father of missing Claudia Lawrence, holds up poster of his missing loved one outside the Houses of Parliament, London, ahead of him giving evidence at the UKs first Parliamentary Inquiry into the rights of families of missing people. (credit:PA)
Missing chef(07 of46)
Peter Lawrence, the father of missing Claudia Lawrence, at the launch of the book 'Gone: The Disappearance of Claudia Lawrence and Her Father's Desperate Search for the Truth' by Neil Root, in Soho, central London. (credit:PA)
Miles for Missing People 10k run(08 of46)
Peter Lawrence father of Claudia Lawrence and Rachel Elias sister of Richey Edwards from The Manic Street Preachers at the start of the Miles for Missing People 10k run, to help the charity that gives support to people who have family members that have gone missing or been abducted abroad or in the UK, at Clapham Common in south west London. The event marks International Missing Children's Day. (credit:PA)
Missing chef(09 of46)
Forensic officers enter the home of missing university chef Claudia Lawrence in Heworth, York, as detectives launch a fresh review of the case. (credit:PA)
Missing chef(10 of46)
Forensic officers enter the home of missing university chef Claudia Lawrence in Heworth, York, as detectives launch a fresh review of the case. (credit:PA)
Missing chef(11 of46)
Forensic officers enter the home of missing university chef Claudia Lawrence in Heworth, York, as detectives launch a fresh review of the case. (credit:PA)
Missing chef(12 of46)
Peter Lawrence, the father of missing Claudia Lawrence, at the launch of the book 'Gone: The Disappearance of Claudia Lawrence and Her Father's Desperate Search for the Truth' by Neil Root, in Soho, central London. (credit:PA)
Missing chef(13 of46)
Police continue searching in St Nicholas Fields nature reserve in York for missing Claudia Lawrence. The 35-year-old of Heworth Road, York, was last seen on Wednesday afternoon at the University of York's Goodricke College and later spoke to her parents on the phone. (credit:PA)
Missing chef(14 of46)
North Yorkshire Police search a field in the Outgang area of York, close to York University, as part of the investigation into the disappearance of Claudia Lawrence. (credit:PA)
Rights for families of missing people(15 of46)
Peter Lawrence, father of missing Claudia Lawrence, reads a statement outside the Houses of Parliament, London, along side Rachel Elias (left), sister of missing Manic Street Preachers guitarist Richey Edwards, and Jacqui Hoyland (right), wife of missing Jeremy Hoyland, ahead of them giving evidence at the UK's first Parliamentary Inquiry into the rights of families of missing people. (credit:PA)
Missing chef(16 of46)
(left to right) Suzy Cooper, Peter Lawrence and Jen King. The father of missing York chef Claudia Lawrence lights a candle on her birthday cake in York today, on the eve of her 36th birthday. He is joined by her friends, the Police Officer in charge of the investigation, and supporters of the Claudia Lawrence Awareness Day. (credit:PA)
Missing chef(17 of46)
Peter Lawrence, 63, the Father of missing York chef Claudia Lawrence, pictured outside King's Cross station, London, where he is appealing to rail passengers to help find and bring home his daughter in time for Christmas. (credit:PA)
Missing chef(18 of46)
Peter Lawrence, the father of missing York chef Claudia Lawrence, is joined by Det. Supt. Ray Galloway, as he releases balloons in York today, on the eve of her 36th birthday. He is joined by her friends, the Police Officer in charge of the investigation, and supporters of the Claudia Lawrence Awareness Day. (credit:PA)
Missing chef(19 of46)
Peter Lawrence stands next to a multi-media screen at Leeds Railway Station, Leeds which is showing an image of his daughter Claudia who has been missing from her York home for over eight months. (credit:PA)
Missing chef(20 of46)
Peter Lawrence (left), father of missing York University chef Claudia Lawrence with James Brennan, Head of Marketing and Sponsorship at York Racecourse holding today's racecard carrying a missing person message inside. (credit:PA)
Missing chef(21 of46)
Peter Lawrence talks to members of the public about his daughter Claudia's disappearance in central York. (credit:PA)
Missing chef(22 of46)
Police officers enter a terraced property in East Parade, Heworth, York as part of the ongoing investigation into missing York University chef Claudia Lawrence. (credit:PA)
Missing chef(23 of46)
North Yorkshire Police handout CCTV image of a pick-up truck which was seen parked outside the house of chef Claudia Lawrence. (credit:PA)
Missing chef(24 of46)
North Yorkshire Police handout CCTV image of a pick-up truck which was seen parked outside the house of chef Claudia Lawrence. (credit:PA)
Missing chef(25 of46)
North Yorkshire Police handout CCTV image of a pick-up truck which was seen parked outside the house of chef Claudia Lawrence. (credit:PA)
Missing chef(26 of46)
North Yorkshire Police handout CCTV image of a pick-up truck which was seen parked outside the house of chef Claudia Lawrence. (credit:PA)
Missing chef(27 of46)
Undated North Yorkshire Police handout photo of the spot on Melrosegate Bridge where a witness saw a man and a woman at 5.35am on March 19 2009. Police are investigating the possibility the woman could have been missing chef Claudia Lawrence. (credit:PA)
Missing chef(28 of46)
Embargoed to 0001 Tuesday April 7 Family handout of the latest poster showing missing York University chef Claudia Lawrence. The poster has been displayed on the campus of York University where she worked. (credit:PA)
Missing chef(29 of46)
The father of missing chef Claudia Lawrence, Peter Lawrence (centre) speaks at a press conference at Church House, in Westminster, London, with Martin Dales (left) and the Director of Services at Missing People, Jo Youle on the three month anniversary of her disappearance. (credit:PA)
Missing chef(30 of46)
Peter Lawrence, the father of missing chef Claudia Lawrence, at a press conference at Church House, in Westminster, London, on the three month anniversary of her disappearance. (credit:PA)
Missing chef(31 of46)
The scene outside the Nags Head pub in York, as police investigating the disappearance of university chef Claudia Lawrence searched the pub, which is near her home, for a second time. (credit:PA)
Claudia Lawrence Crimewatch reconstruction(32 of46)
An actress is filmed walking down Melrosegate in York during the filming of a reconstruction for BBC programme Crimewatch reconstructing the last known movements of missing York University chef Claudia Lawrence in York. (credit:PA)
Claudia Lawrence Crimewatch reconstruction(33 of46)
An actress is filmed walking down Melrosegate in York during the filming of a reconstruction for BBC programme Crimewatch reconstructing the last known movements of missing York University chef Claudia Lawrence in York. (credit:PA)
Claudia Lawrence Crimewatch reconstruction(34 of46)
An actress is filmed walking down Melrosegate in York during the filming of a reconstruction for BBC programme Crimewatch reconstructing the last known movements of missing York University chef Claudia Lawrence in York. (credit:PA)
Claudia Lawrence Crimewatch reconstruction(35 of46)
An actress is filmed accepting a lift in a car in Melrosegate, York during the filming of a reconstruction for BBC programme Crimewatch reconstructing the last known movements of missing York University chef Claudia Lawrence in York. (credit:PA)
Launch of website to find Claudia(36 of46)
Martin Dales, friend and spokesman for Peter Lawrence, launches the website www.findclaudia.co.uk during a press conference at the Worsley Arms Hotel, Hovingham, York. Peter Lawrence's daughter Claudia has been missing for 50 days. (credit:PA)
Claudia Lawrence Press Conference(37 of46)
Peter Lawrence the father of missing York woman Claudia Lawrence at a Press Conference at York Police Station today where Det. Supt. Ray Galloway the Detective in charge of the investigation revealed the Police were now treating it as a murder inquiry. (credit:PA)
Claudia Lawrence Press Conference(38 of46)
Peter Lawrence (Left) the father of missing York woman Claudia Lawrence at a Press Conference at York Police Station today where Det. Supt. Ray Galloway (Right) the Detective in charge of the investigation revealed the Police were now treating it as a murder inquiry. (credit:PA)
Missing chef(39 of46)
EMBARGOED TO 0001 TUESDAY APRIL 20. Peter Lawrence (right) with his spokesman Martin Dales, in Slingsby near Malton today as his daughter Claudia Lawrence remains missing. (credit:PA)
Missing chef(40 of46)
Detective Superintendent Ray Galloway, the North Yorkshire police detective in charge of the investigation into missing chef Claudia Lawrence, speaks to the media at York Police Station today. (credit:PA)
Missing chef(41 of46)
Embargoed to 0001 Wednesday April 15 Peter Lawrence, left the father of missing chef Claudia Lawrence and Shaun McDonnell, sales director of York firm Flourish Innovations Ltd - the manufacturers of the Filpot with a 'Filpot' table-top box displaying images of missing chef Claudi Lawrence who has been missing for four weeks. (credit:PA)
Missing chef(42 of46)
The Reverend Canon John Manchester (left) walks with Peter Lawrence (centre), father of missing Claudia Lawrence and family friend Martin Dales, outside St Mary's Priory Church, Old Malton, North Yorkshire. (credit:PA)
Missing chef(43 of46)
Embargoed to 0001 Tuesday April 7 Peter Lawrence, father of missing York University chef Claudia Lawrence, during a personal press briefing at his home in Slingsby near Malton, North Yorkshire. (credit:PA)
Missing chef(44 of46)
Police continue searching in St Nicholas Fields nature reserve in York for missing Claudia Lawrence. The 35-year-old of Heworth Road, York, was last seen on Wednesday afternoon at the University of York's Goodricke College and later spoke to her parents on the phone. (credit:PA)
Missing chef(45 of46)
The father of missing chef Claudia Lawrence, Peter Lawrence at a press conference appealing for information about his daughter's whereabouts, in Fulford Road police station in York. (credit:PA)
Missing chef(46 of46)
Police continue searching in St Nicholas Fields nature reserve in York for missing Claudia Lawrence. The 35-year-old of Heworth Road, York, was last seen on Wednesday afternoon at the University of York's Goodricke College and later spoke to her parents on the phone. (credit:PA)