Levi Bellfield has made a formal complaint to Surrey Police denying he confessed to the murder of Milly Dowler.
Two days after her family went public with details of his confession to police, Bellfield, 47, has claimed he never admitted abducting, raping or murdering the 13-year-old.
He has challenged police to prove he confessed.
Bellfield's solicitor has written to two senior offices at the Surrey Police force, implying covert recording techniques were used during an informal interview and demanding "the tape recording of the alleged confession".
The letter, where Bellfield is referred to as Yusuf Rahim, the name he took after converting to Islam, claims he was being formally interviewed in prison under the terms of the Police and Criminal Evidence Act about other murders police believe he may have committed.
It then says the tape recorder was turned off and the officers informally asked him about Milly Dowler. No solicitor was present.
His solicitor, Julie Cooper, wrote: “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.”
Bellfield was found guilty of the murder of Amanda "Milly" Dowler in 2011 and sentenced to life in prison. She was abducted on the way home from school in Walton-on-Thames, Surrey, in March 2002.
