He tirelessly campaigned to find his missing daughter, as well as the missing relatives of other families, but died aged 74 after a short battle with an illness.
Despite the loss of Peter, Claudia Lawrence’s family continue the search for their loved one.
In a statement they said: “Despite Peter’s death, the message remains the same – where is Claudia? Anyone with information should contact North Yorkshire Police on 101.”
Here’s what is known about her disappearance.
Who is Claudia Lawrence?
Born in Malton, Yorkshire, and educated at York College for Girls, Claudia Lawrence was working as a chef at the time of her disappearance in 2009.
She was employed by University of York's Goodricke College and was considered punctual and reliable by her employers.
She was 35 at the time of her disappearance.
When was she last sighted?
On March 18, 2009, Miss Lawrence spoke with her parents over the phone and, at 8.23pm, sent her friend a text.
Earlier on that day she had worked at the University of York, finishing her shift at 2.30pm before embarking on the three mile walk to Heworth Road. She was spotted by a friend at 2.50pm who gave her a lift home.
A friend later saw her outside her home at 3.05pm after she had posted a letter.
She has not been seen or heard from since.
Missing persons investigation
Peter contacted North Yorkshire Police after his daughter failed to keep an arrangement to meet a friend at the Nags Head pub where she regularly frequented. She also failed to attend work on March 19.
Claudia was due to walk the three miles to work on Thursday 19 March for a shift beginning at 6am. But she never turned up for work on that day. Her mobile phone – a silver Samsung D900 – and blue and grey Karrimor rucksack in which she carried her chef’s whites, have never been found.
The absence of those items led police to believe that she had left home for work on the morning of March 19.
It was discovered that Lawrence’s phone had been deliberately switched off at 12.10pm on the day of her disappearance.
Five months after her disappearance North Yorkshire Police started treating her disappearance as a suspected murder investigation.
What are the main theories about her disappearance?
The original investigation into her disappearance considered four key theories.
Police initially explored the idea that Lawrence disappeared on her own accord. She was known to visit Cyprus and had made friends on the island whom she stayed in contact with when back in the UK, and detectives visited Cyprus as part of the investigation. Her family were insistent that Lawrence would have contacted them and this theory was eventually dismissed.
Another theory considered that Lawrence might have encountered a serial killer or crazed individual on her way to work. Reports of suspects behaving strangely were made during the appeal to find Lawrence but police discounted the idea of a serial killer being involved in the disappearance of Lawrence. The Senior Investigating Officer in the murder of Sian O'Callaghan, Stephen Fulcher has suggested that Lawrence may have been a victim of serial killer Christopher Halliwell.
Police also investigated whether Lawrence may have suffered a medical emergency on her way to work though this was quickly dismissed.
The initial investigation settled on the theory that Lawrence was the victim of a person known to her.
Dt Supt Ray Galloway changed the public perception of the case during an appearance when during an appearance on BBC’s Crimewatch he suggested that Lawrence may have been engaged in relationships secret to her family.
He said: “as the investigation has developed it’s become apparent that some of Claudia’s relationships had an element of complexity and mystery to them. I’m certain that some of those relationships were not known to her family or friends.” Family and friends have dismissed this theory that she was entangled in secretive relationships.
A Major Crime Unite review of the case carried out a forensic search of Claudia’s home and car. They found a man’s DNA and fingerprints in her car. Six men were arrested on suspicion of murder but were subsequently released.
On the tenth anniversary of when she was last seen, North Yorkshire Police said they are still waiting for information from the public to help them make major progress.
Anyone with information about the disappearance of Claudia Lawrence should contact North Yorkshire Police on 101.