Levi Bellfield has finally admitted the abduction, rape and murder of schoolgirl Milly Dowler - more than 13 years after her body was found in Yateley Heath Woods, near Fleet.
The 47-year-old was in June 2011 found guilty of murdering the 13-year-old after abducting and raping her while she walked home from school.
Despite his conviction, and whole life sentence, this is the first time Bellfield has made such admissions to police.
On Wednesday, detectives from the Surrey and Sussex Major Crime Team said they arrested and released a man in his 40s in relation to allegations of rape and assisting an offender.
The force said the arrest followed new information about an accomplice involved with Bellfield in the abduction and rape of Dowler, but not her murder.
Detectives say while they "thoroughly investigated" the claim, the man was subsequently released with no further action as no evidence was found to support the allegations.
However, during this investigation, police said they also spoke to Bellfield, who "has admitted his responsibility for the abduction, rape and murder of Milly Dowler".
Surrey Police launched Operation Ruby following the disappearance of Milly Dowler in 2002 when she was on her way home from school in Walton.
In a statement, Milly's family said: "The Dowler family has been made aware of the recent arrest.
"They have been aware for some considerable time that a police investigation was taking place into the circumstances of the abduction and murder of Milly.
"The effect of this information has been devastating for a family which has already had to endure so much.
"We must stress how important it is that, notwithstanding this development, the Dowler family should be afforded privacy and space to go about their lives, and we are grateful for the consideration of the public and media in that regard."
Bellfield was found guilty of abducting and killing 13-year-old Milly following a trial held at the Old Bailey in London in June 2011
In February 2012, the 6ft 1in, 20-stone killer lost his bid to challenge his conviction at London's Court of Appeal and will serve the remainder of his sentence.
Bellfield was already in jail for the murders of Amelie Delagrange and Marsha McDonnell, and the attempted murder of Kate Sheedy, when he went on trial accused of killing Milly.
In 2008, he had been given a whole life term for murdering Ms McDonnell, 19, in 2003, and murdering Ms Delagrange, 22, and attempting to murder Ms Sheedy, 18, in 2004.
Additional reporting by Mirror Online .