Levi Bellfield has denied confessing to the abduction, rape and murder of schoolgirl Milly Dowler, Surrey Police has said.
According to The Telegraph, a letter has been sent to police by his lawyer Julie Cooper, challenging the force to 'prove' the confession.
In the correspondence, Bellfield's solicitor accuses the police of covertly taping the convicted killer while asking him 'informal' questions about the murder of Milly Dowler.
She has demanded that the police produce the taping of Bellfield's alleged confession.
The letter suggests the police were questioning Bellfield, also known as Yusuf Rahim, about other murders they believe that he was involved with and without a solicitor present, when officers turned off the tape recorder and asked him about Milly Dowler's death.
The letter says: "We request the tape recording of the alleged confession; the attendance notes relating to the alleged confession; the circumstances surrounding the alleged confession and we would be grateful if you would confirm or deny whether a covert tape was being used during the course of the interview with Mr Rahim and we look forward to your early response.”
Surrey Police confirmed they received the correspondence from Bellfield's solicitors, and that it stood by its original statement from 27 January when the force said Bellfield had confessed.
The denial comes after the Dowler family revealed this week the gruesome details that Bellfield allegedly gave to two female police officers in relation to Milly's final hours.
In the statement they revealed the "unimaginable pressure" the information had placed on them as a family and added: "Now we know the final hours of Milly's life, perhaps her soul, at long last, can finally rest in peace."
Colin Sutton, the former Scotland Yard detective whose investigation into the murders of three other young women put Bellfield in prison, said the killer's claims were "breathtaking".
He told the Press Association: "I am almost lost for words on this. He has been toying around with the police and also the victims' families, particularly the Dowlers.
"It is even beyond the cruel, wicked games that I know he was capable of. This is almost beyond what I thought even he was capable of."
Mr Sutton added that he would be surprised if Surrey police did not have an "unassailable record" of Bellfield's confession.
He said: "I would be astounded if Surrey Police did not have some sort of proper, decent, thorough corroboration of his claims, because when you are dealing with somebody like him you would not go public with it unless you had that.
"Given the high profile nature of this case and who he is I would be absolutely astounded if there isn't some sort of unassailable record of these confessions."