Joanne Nelson's family thought her boyfriend idolised her.
Dyson made a tearful appeal for Miss Nelson to come home
But on Valentine's Day this year Paul Dyson called the police in Hull to report Miss Nelson missing.
During the 14-minute call he played the part of a worried boyfriend. He was asked had there had been a row. "No, nothing like that," Dyson replied.
It was all a lie which he later repeated when, in tears, he appealed on television for his girlfriend to come back home.
He claimed the couple had exchanged Valentine cards and kissed and cuddled before she left for work on the Monday morning.
The truth was that three days earlier he had killed her. And over the next few days his story began to unravel as police searched the house he shared with Miss Nelson in Hotham Road North, Hull.
He had been caught on CCTV at his corner shop buying bin bags and cleaning products the day before he reported his girlfriend missing.
On Sunday 13 February Dyson bought bin bags in his local shop
The police arrested Dyson, aged 30, and after two days he confessed to killing her. On Monday he pleaded guilty in court to her murder.
He told officers he wrapped the 22-year-old's body in bin bags and then drove towards York.
He said he left her body close to a metal gate which had some green bottles by it.
The police spent hours driving him around East and North Yorkshire but he never could - or would - remember where the gate was.
It was to become the biggest search Humberside Police had ever undertaken.
The five weeks of searching were hampered by the winter weather, but then there was a breakthrough.
Forensic analysis of Dyson's clothing found a number of spores and pollen, including a type of yew which is rare in the north of England.
Botanical maps were used to find where these plants grow and this took the operation north of York around Castle Howard.
Det Supt Ray Higgins was driving near Bandsby trying to find a place on which the search teams could focus. But when he saw a gate he stopped the car.
"We had a steel gate which opens outwards. It is supported by two wooden posts and it had rabbit netting to each side, exactly as Dyson had described it to us," he explained.
Dyson had said Joanne was near the entrance but 30 yards along the track after the gate the detectives had still not found her.
Then they came to a large dip.
Mr Higgins said: "The first thing I saw was the shape of a bin bag. Looking at it more closely you could see the bin bags had been wrapped with clear tape.
"I realised then and there that in reality the search was over and we had found Joanne."