Milly Dowler's phone messages a mystery, police say
The truth about how two voicemail messages on Milly Dowler's phone were deleted may never be known, the Leveson Inquiry into media ethics has heard.
Det Ch Insp John MacDonald said it remained unclear whether they were deleted automatically or deliberately.
In July 2011, the Guardian said News of the World reporters deleted messages, giving her family false hope she was alive and prompting the inquiry.
The Dowler family praised the Guardian and said they had faith in the inquiry.
The Metropolitan Police confirmed Milly's voicemail was hacked after she went missing.
But the inquiry at the Royal Courts of Justice in London heard that incomplete records and the lapse of time meant it would never emerge how two of the messages were deleted.
The Met said in their statement they believed some individual voicemails were automatically deleted 72 hours after they had been listened to.
'False hope moment'
Det Ch Insp MacDonald said he could not "conclusively" say whether any voicemails were manually deleted.
But his statement added: "There do appear to have been two messages missing that should have been present when Surrey Police carried out their second recorded download on April 17.
"It is not known why that happened and it will not now be possible to provide an explanation."
The inquiry has previously heard that Milly's mother Sally called her daughter several times in March 2002 after she vanished walking home from school in Walton-on-Thames, Surrey.
She said she believed she was alive because she was able to leave a message, after previously not being able to.
Milly had a generic voicemail message on her phone that indicated when her message box was full. If a message was deleted the greeting would revert to her own personal greeting.
The 13-year-old's remains were found in Hampshire six months after she went missing.
Former bouncer Levi Bellfield was jailed for life in June 2011 after being found guilty of abducting and killing her.
The News of the World - which was forced to close over the hacking scandal - has previously admitted intercepting the teenager's voicemails.
The Met Police statement said "the false hope moment is likely to have occurred after an automatic purge" of messages.
Responding to the police statement, the Dowler family said: "If Surrey Police had prosecuted this activity in 2002 then the position would have been very different."
The family added: "Perhaps countless others might also have avoided having their private messages hacked into by the News of the World."
They praised the "relentless efforts of one journalist" and said they had faith that the journalist's efforts, the inquiry and that Operation Weeting (Met's inquiry into hacking) would have a lasting positive impact.
Commenting on the evidence, the Guardian insisted it had had no wish to cause distress to the Dowler family.
In a statement read to the inquiry, the paper's head of legal Gill Phillips said the paper's story of 4 July 2011 had been based on multiple sources.
"Our error - as we acknowledged and corrected last December - was to have written about the cause of the deletions as a fact rather than as the belief of several people involved in the case. We regret that.
"After five more months of intensive inquiry, the police have found that the passage of time and the loss of evidence means that 'reaching a definitive conclusion is not, and may never be, possible'."