Sussex Police should have asked why no information about Milly Dowler's hacked phone was included in the investigation into her disappearance, an MP has said.
The force was asked to review Surrey Police's handling of the investigation into the murdered schoolgirl.
Evidence has now been uncovered that Surrey Police knew Milly's phone had been hacked by the News of the World but did not include this information in its investigation.
Keith Vaz, the chairman of the Home Affairs Select Committee, said: "Had Surrey Police acted in 2002, it may have prevented the culture of hacking becoming endemic at News of the World.
"This was a serious omission.
"The committee will be investigating further the reasons why Surrey Police did not follow up on this evidence, and why Sussex Police did not flag it up in their review of Operation Ruby."
A Sussex Police spokesman said: "It is normal practice for external forces to review unsolved major investigations at different stages.
"Sussex Police conducted an early review of Surrey Police's investigation into the disappearance of Milly Dowler.
"We will confirm the parameters of this review and provide a response to interested parties as soon as we are able."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article