Here is a timeline of missing university chef Claudia Lawrence's last known movements and the subsequent investigation since her disappearance:

2009 March 18 :: 5.57am - Miss Lawrence is captured on CCTV arriving for work at the University of York's Goodricke College.

:: 2.31pm - The chef leaves work to walk the three miles to her home on Heworth Road. A female colleague sees her as she drives past in her car and gives her a lift, dropping her off outside her house.

A short time later, Miss Lawrence leaves her house and walks past the Nags Head pub. She has a brief conversation with a woman with a pram.

:: 3.05pm - The last sighting of Miss Lawrence as she walks back to her house.

:: 8.10pm - Miss Lawrence has a telephone conversation with her father, Peter, and then another with her mother, Joan.

:: 8.23pm - She sends a text message to a friend.

:: 9.12pm - Miss Lawrence receives a text on her mobile phone but it is not known if she read the message.

March 19 :: 6am - Miss Lawrence fails to arrive for her shift at work.

:: Later in the evening, Miss Lawrence fails to keep an arrangement to meet her friend, Suzy Cooper, at the Nags Head pub. Ms Cooper discovers her friend did not attend work and rings Mr Lawrence, who contacts North Yorkshire Police.

March 23 :: Mr Lawrence, a solicitor from Slingsby, North Yorks, makes an emotional appeal for information about his daughter at a news conference in York. He describes Miss Lawrence's disappearance as a ''living nightmare''.

:: Police say they cannot rule out the possibility that the chef has been abducted.

March 25 :: Detective Superintendent Ray Galloway, leading the investigation, says he believes Miss Lawrence may have come to harm after meeting someone she knew. He confirms upwards of 100 police officers are involved in the search and says North Yorkshire Police are bringing in officers from other forces to help.

:: CCTV footage of the chef's last known movements are released.

March 30 :: Mr Galloway makes an appeal for information on BBC One's Crimewatch programme.

April 7 :: Mr Lawrence holds his first weekly press conference at his home and appeals for anyone protecting his daughter's possible abductor to come forward.

April 16 :: Police say they are investigating ''significant'' new lines of inquiry, including a couple seen arguing near a car on Miss Lawrence's route to work the day after she was last seen and two men apparently trying the front door to her house in the week before she disappeared.

April 24 :: Detectives say they are treating Miss Lawrence's disappearance as a suspected murder investigation and Crimestoppers offers a £10,000 reward for information leading to the conviction of those responsible.

Mr Galloway also reveals new information received from members of the public. He says one witness reported seeing a man and a woman walking near the University of York between 6am and 6.30am on March 17 and March 19. Another witness saw a man and a woman, possibly matching Miss Lawrence's description, at 5.35am on March 19 on Melrosegate on the chef's route to work.

April 29 :: Mrs Lawrence releases her first statement through police describing her daughter's disappearance as ''every parent's worst nightmare''.

May 6 :: Police reveal they have received more than 1,000 calls about Miss Lawrence's disappearance since March 22 and have taken 1,096 statements and reports. Officers involved in the investigation have visually searched around 1,270 properties, including gardens and outbuildings and student halls of residence at the University of York.

May 15 :: Police release CCTV footage of a man seen near Miss Lawrence's home in the early hours of March 19. Mr Galloway says the number of searching officers has been scaled-down and police are now only carrying out intelligence-led searches.

June 2 :: A reconstruction of Miss Lawrence's last known movements and possible witness sightings is screened on BBC One's Crimewatch programme.

Mr Galloway tells the programme that Miss Lawrence was involved in relationships of ''complexity and mystery'' and appeals to anyone who had ever been in a relationship with the chef to come forward.

August 19 :: Police say an external review of the investigation by the National Policing Improvement Agency (NPIA) is ''extremely positive'' and the force are acting upon a list recommendations.

September 18 :: Detectives reveal they have extended their investigation to Cyprus.

2010 March 18 :: Police reveal Ms Lawrence spent the night with a mystery boyfriend just two days before she went missing. It was ''critical'' they spoke to the man, a detective adds.

March 24 :: Detectives search an area near the University of York following new information.

May 6 :: Mr Lawrence calls for an urgent independent inquiry into the police investigation of his daughter's disappearance and suspected murder.

He claims North Yorkshire Police has developed a ''bunker mentality'' and has been ''rude and dismissive'' towards members of the public contacting them with information. The force says it has received no complaints from members of the public about its officers. They describe the inquiry as ''thorough, professional and challenging''.

May 25 :: Police confirm they have spent two days searching a house about 10 miles from Claudia's home as a result of a ''recent development''.

July 29 :: Police confirm they are scaling back the number of officers dedicated to the inquiry.

Assistant Chief Constable Tim Madgwick says 100 officers were dedicated to the investigation at its height.

A year after Miss Lawrence disappeared, this figure had dropped to about 20 to 30 and there were now 16 detectives involved. Mr Madgwick says will be cut to seven officers the following month.

August 8 :: A man arrested on suspicion of burglary has been spoken to about the case, North Yorkshire Police say. But he is described as ''one of many people spoken to during the course of the investigation'' and there still have been no formal suspects identified by the inquiry team.

September 20 :: Mr Lawrence speaks of his ''devastation'' after it is revealed that a cash reward for information was being dropped.

The decision means North Yorkshire Police will remove their appeal posters from fleet vehicles because they refer to the reward.

2011 March 18 :: On the second anniversary of Miss Lawrence's disappearance, Mr Galloway reveals that he could have ''potentially'' spoken to her killer.

December 13 :: Detectives say they are pursuing a new lead which could be ''significant''.

2012 March 16 :: Mr Lawrence speaks of his daily pain over his daughter's disappearance and makes a plea for anyone who may still harbour a sense of ''misguided loyalty'' to come forward and help with the police investigation.

July 10 :: Martin Dales, spokesman for Mr Lawrence, says a former private detective has contacted him to say he spotted someone with a striking resemblance to Claudia a week earlier in Amsterdam.

2013 February 27 :: Family and friends of the missing chef make an emotional appeal for help to find her on what would have been her 39th birthday.

October 29 :: Police announce that a new forensic search of Miss Lawrence's home is to begin as they launch a fresh review of the case.

2014 March 17 :: Mr Lawrence, speaking ahead of the fifth anniversary of his daughter's disappearance, says not knowing what happened to his daughter five years after she disappeared is like a ''cancer'' eating away at him.

March 19 :: Police say a new forensic examination of Claudia's house has uncovered the fingerprints of people who still have not come forward five years after she disappeared.

They say they are seeking to trace two men and two vehicles seen near her home.

April 17 :: North Yorkshire Police say 121 people have come forward to help their inquiry since a national appeal was made to coincide with the fifth anniversary of her disappearance. They say taxi drivers may have important information about the case.

May 13 :: A 59-year-old man is arrested on suspicion of murder by detectives investigating the disappearance. Police search two houses in York and North Shields. The man is released on police bail the following day and released without charge on November 17.

2015 February 25 :: Detectives search an alleyway at the back of Miss Lawrence's home.

March 18 :: Police appeal for help to identify two people caught previously unseen on CCTV walking near Miss Lawrence's home on the evening of her disappearance.

March 23 :: A man in his 50s is arrested on suspicion of Miss Lawrence's murder and is released on police bail the following day. A home in York is searched.

April 14 :: A 47-year-old man arrested on suspicion of perverting the course of justice is released from police bail. North Yorkshire Police say he provided information which has progressed the investigation.

April 22 :: Three men, in their 50s from the York area, are arrested on suspicion of murder but released on bail the following day. Three houses are searched by police.

September 17 :: North Yorkshire Police say a file of evidence on four men arrested on suspicion of murder will be sent to the Crown Prosecution Service so it can consider whether to bring charges. The man are released from bail.

2016 March 8 :: Police say the Crown Prosecution Service has decided the four men will not face charges.