The News of the World interferred with the police inquiry into the disappearance of the Surrey schoolgirl Milly Dowler by hacking into her mobile phone, police sources have confirmed.
In the latest blow to Rupert Murdoch's News International, Scotland Yard detectives have found evidence that the Sunday paper targeted the 13-year-old's mobile phone in March 2002, soon after she disappeared on her way home in Walton-on-Thames.
The tabloid - then being edited by News International's current chief executive Rebekah Brooks - deleted messages left on her phone by desperate friends and relatives to free space in her inbox, so that it could access fresh voicemails for stories.
This led Surrey Police and the Dowler family to believe that she may have been still alive.
The NOTW later ran a story based on a hoax message left on her voicemail and also carried a heartrending interview with the Dowler family, unaware that their false hope had been at least partly stirred by its own act of criminality.
It is understood the mobile phones of Milly's parents, Robert and Sally, were also targeted.
By then Milly had been murdered by Levi Bellfield, jailed for life last month.
Mark Lewis, their solicitor, said the Dowlers had been informed about the phone hacking by officers from Operation Weeting, the Yard's new investigation into phone hacking by the private investigator Glenn Mulcaire.
Mr Lewis said: "I would suggest this is one of the worst cases of all. You have to ask the question: who at the News of the World was thinking it was appropriate to try to hack into the phone of a missing young girl?" He added: "Sally and Bob Dowler have been through so much grief and trauma without further distressing revelations to them regarding the loss of their daughter."
The latest twist in the long-running scandal is likely to increase the pressure on Ms Brooks.
Labour MP Tom Watson said targeting Milly Dowler's phone was a "despicable and evil act".
News International said: "This particular case is clearly a development of great concern and we will be conducting our own inquiries as a result."