The messages were deleted by journalists in the first few days after Milly’s disappearance in order to free up space for more messages. As a result friends and relatives of Milly concluded wrongly that she might still be alive. Police feared evidence may have been destroyed.
Even today, it’s unclear whether what The Guardian reported is actually wrong that NotW caused the deletion that gave false hope to Dowler’s family. Davies reports this:
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.
What we do know is that police can’t prove who deleted that message but think it’s unlikely that NotW did it, since Glenn Mulcaire hadn’t been hired on the story yet (although Davies reports another NotW journalist may have already had Dowler’s cell number and PIN).
Even The Guardian can’t get this aspect nailed down, writing that NotW responsibility is now believed “unlikely” in the same sentence that it writes that “this was not the case”:
In July the Guardian reported that the deletions were caused by the News of the World. But, as it emerged that this was not the case, the newspaper printed a clarification in mid-December saying that was “unlikely to have been correct” in the light of further investigation made by the Metropolitan police.
British reporting and writing is a little loosey-goosey for our tastes. That goes for language and attribution. Both are critical. In this case, we see how sloppily excluding a few words can damage a reporter’s and paper’s credibility. When you’re dealing with ultra-sensitive investigations of highly powerful people, you have to be that much more careful. Davies and The Guardian, who are still real heroes, despite the error, have opened themselves up to attack from someone like Rupert Murdoch and his minions. That’s dangerous, even if it’s too late for Murdoch to regain his former prominence in the UK.
Fortunately, almost all of Davies’ other reporting has held up to scrutiny—no small feat in one of the biggest—perhaps the biggest—media stories of all time, on which he has written more than a hundred pieces. But the fundamentals of journalism—attribution and accuracy—apply even to the best journalists and their biggest scoops.