Fresh details of the hacking of Milly Dowler's phone by the News of the World have been obtained by the police, the Guardian has learned.
According to sources familiar with the case, officers from Operation Weeting have unearthed logs detailing the hacked messages from tearful members of the murdered girl's family.
It is understood that while News of the World reporters probably were responsible for deleting some of the missing girl's messages, police have concluded that they were not responsible for the particular deletion which caused her family to have false hope that she was alive.
Detectives told Milly's parents in April that the paper's journalists had intercepted and deleted messages on the murdered teenager's phone. Evidence has now revealed that Milly's phone would automatically delete messages 72 hours after being listened to.
This means the paper's journalists would have inadvertently caused some voicemails to be deleted after they began listening to them, but police found that some messages had also been deleted before the News of the World began hacking into her voicemail.
The paper's activities hampered Surrey police inquiries at the time, promoting a wild goose chase.
David Cameron described the way journalists listened to Milly's friends and family pleading with her to get in touch as "disgusting". Rupert Murdoch called it "abhorrent". He closed down the paper, apologised to the Dowlers and paid £3m to the family and a number of charities.
Operation Weeting's latest findings confirm the Guardian's report that Surrey police knew about the tabloid's phone hacking at the time and took no action; and that the News of the World hired a second private investigator, Steve Whittamore, to "blag" information about the Dowler family from confidential telephone records.
Testifying to the Leveson inquiry, Sally Dowler described how one day after Milly went missing she found that her daughter's voice mailbox had apparently been emptied. "I just jumped and said 'She's picked up her voicemails, she's alive'," she told the inquiry.
Evidence retrieved from Surrey police logs shows that this "false hope" moment occurred on the evening of Sunday 24 March 2002. It is not clear what caused this deletion. Phone company logs show that Milly last accessed her voicemail on Wednesday 20 March, so the deletion on Sunday cannot have been the knock-on effect of Milly listening to her messages. Furthermore, the deletion removed every single message from her phone. But police believe it cannot have been caused by the News of the World, which had not yet instructed private detective Glenn Mulcaire to hack Milly's phone.
Police are continuing to try to solve the mystery.
The Dowlers' lawyer, Mark Lewis, said last night that although Mulcaire had not been instructed by email at the time of Sally Dowler's "false hope" moment, it remained possible that the voicemails had been deleted by a News of the World journalist, or that Mulcaire had been instructed earlier by phone.
The original police theory was that journalists had deliberately deleted some messages because Milly's voicemail box had filled up, and they wanted to be able to listen to more.
In August, the Wall Street Journal disclosed that on 11 April 2002, three weeks after Milly's disappearance, the News of the World sent at least eight reporters and photographers to stake out a Midlands factory because they believed Milly was still alive and was trying to get work there.
They found nothing and ran a short story in that week's paper. In early editions it included direct quotes from three of Milly's voicemails. It was at about this time that the News of the World formally approached Surrey police to tell them what it had heard on the missing girl's voicemail.
Two representatives of the paper are believed to have met detectives in the incident room at Staines police station. The police, however, took no action against them. Scotland Yard has arrested a total of 18 people and has suggested that there may possibly be as many as 6,000 victims of voicemail interception by the paper. They are also investigating allegations of email hacking and the payment of bribes to police officers.
Lewis said: "The Metropolitan police earlier this year told Bob and Sally Dowler that in 2002 the News of the World had listened to their missing daughter's voicemail and deleted some of the messages.
"Mrs Dowler linked this to an incident when Milly's voicemail had suddenly ceased to be full and which had given her 'false hope'. There is no doubt that there had been deletions by someone other than Milly, and the deletions had not been triggered by Milly's own actions."
He added: "It remains unchallenged that the News of the World listened to Milly Dowler's voicemail and eavesdropped on deeply personal messages which were being left for her by her distraught friends and family."