Hours after police arrested the Crossbow Cannibal, he not only admitted murdering the three missing Bradford sex workers but boasted that he had killed "loads" more victims.
More reports and background on Stephen Griffiths
During an interview at Halifax police station on May 24, Stephen Griffiths told detectives there was no point in continuing their search for Susan Rushworth, Shelley Armitage and Suzanne Blamires because they were already dead.
But he refused to reveal where he had hidden their bodies and then claimed to have killed more, although he refused to name his other victims.
The chilling claim, which Griffiths retracted in another interview the following day, sparked a major inquiry which has involved every police force in the country checking their catalogues of unsolved murders and missing person investigations.
Although Griffiths has maintained ever since that he has only killed three women, criminologists are compiling a timeline of his movements since the age of 14 to check for any potential links between the Bradford murders and other cases.
"To date, there is no evidence linking him to any others," said Acting Detective Chief Superintendent Andy Brennan, the acting head of West Yorkshire Police's Homicide and Major Enquiry Team. Whether he claimed to have killed more to be boastful or for his own kudos, I don't know.
"We have dismantled everything in his flat and, if there were any tissue or blood belonging to another victim, we would find it. But, even after all this time, we haven't linked him to any crime other than the murder of these three girls.
"We are building up a timeline for him, tracing his movements back to when he was 14 or 15. The forensic work will go on simultaneously and we will give him the opportunity to be interviewed again."
Several unsolved murders in Yorkshire have come under the microscope, including investigations into the deaths of prostitutes Rebecca Hall, Yvonne Fitt and Vicky Glass.
Miss Hall's stripped and battered body was found on April 26, 2001 in an alleyway off Thornton Street, Bradford, half a mile from Griffiths's block of flats.
Forensic scientists initially believed that the 19-year-old mother -of-one, who had been missing since April 13, was abducted and held for several days before she was murdered.
But detectives later ruled out that theory, determining she was killed on the night she went missing, possibly with a hammer, and her body had lain undiscovered for 13 days.
Police uncovered evidence Miss Hall had been lured into drugs and prostitution, unbeknown to her family, when she was only 14 or 15. At 16 she was abducted by two men who raped her and held her with another woman for several days.
Detectives explored links between Miss Hall's case and the murders of two other prostitutes, Michaela Hague in Sheffield and Carly Bateman in Bolton.
Geoffrey Porter, from Wigan, was jailed for life in 2002 for Miss Bateman's murder, but Miss Hague's killer has never been caught.
The body of Miss Fitt, who worked as a prostitute in Bradford and Leeds, was found in a shallow grave at Warren Point, Norwood Edge, between Otley and Pateley Bridge, on September 12, 1992.
Discovered by a man collecting mushrooms at the beauty spot, the body was so badly decomposed it took forensic experts five days to establish that Miss Fitt, 33, had been murdered.
More than 600 people have been interviewed about the murder, but the killer has never been traced.
The body of Miss Glass, 21, who worked as a prostitute in Middlesbrough, was found dumped on moorland near Danby, North Yorkshire, in November 2000.
Cleveland Police's hunt for her killer has stretched beyond North Yorkshire and Teesside as she was known to travel with lorry drivers, but no-one has been charged with the murder and there have been no arrests in the case since 2002.
Details of the Griffiths case have also been shared with murder squad detectives investigating the disappearance of several women who were not involved in the sex trade.
North Yorkshire Police officers searching for the missing York chef Claudia Lawrence have liaised with colleagues in West Yorkshire to establish whether she may have come into contact with Griffiths.
Miss Lawrence was last seen walking near her Heworth Road home after finishing work on March 18 last year.
Police upgraded the inquiry to a murder investigation the following month.
Another notable Yorkshire case is the disappearance of Gemma Simpson, who was 24 when she disappeared in May 2000 after a row with her elder sister Naomi.
She lived in a flat in Compton Terrace, Harehills, Leeds, and was last seen boarding a bus heading for the city centre. She had told a friend that she was going to see another friend in Huddersfield.
Police travelled to Amsterdam after receiving reports that Miss Simpson may have gone there, but the trip failed to open any new significant lines of inquiry.
The death of Bradford schoolgirl Nobantu Zani in September 1995 also remains a mystery.
The South African-born 15-year-old, known as Mandy, was found dead at a crag known as Druid's Altar, on moorland above Bingley.
Case is far from over, say police
TRAWLING through the police database to find more potential victims will be the third and final phase of Operation Pinstripe, the investigation into Stephen Griffiths's crimes.
Police have interviewed Griffiths twice since he was charged with the Bradford sex worker murders and the officer leading the investigation, Det Supt Sukhbir Singh, said the case was far from being over.
"The first (phase) was to secure evidence to charge Griffiths, the second was to secure his conviction those have both been done.
"We now move on to the third phase which will involve reviewing a comprehensive timeline to see if he can be linked with any other disappearances. This will include working with our partners and colleagues nationally and locally looking at his movements to see if there are any links between him and other disappearances and murders."