In the two years since Milly Dowler disappeared there has been no let up in the investigation to find her killer.
Milly Dowler's body was found six months after she disappeared
Fifty detectives are still dedicated to discovering who murdered the Surrey schoolgirl, whose body was found six-months after she vanished on 21 March 2002.
On the second anniversary of the 13-year-old's disappearance, police have renewed their appeal for help from the public - convinced someone knows the identity of the murderer.
With a £50,000 reward still being offered in the case, police are confident the killer must have confided in a friend or relative.
Speaking to BBC News Online, Det Ch Insp Brian Marjoram, senior detective in the case, said: "Past experience tells us from similar investigations that generally people close to the offender are aware that something has happened, and in some cases the offender does reveal what has happened.
"There is a real possibility that there is someone other than the killer who knows what has happened."
Milly Dowler was last seen walking home from Walton-on-Thames railway station after catching a train from Heathside School in Weybridge.
Her body was found six months later on 20 September in Yately Heath Wood in Hampshire.
Surrey Police chief constable said Milly's case had "touched souls"
Investigations have been extensive - nearly 4,000 statements taken from members of the public, more than 6,000 calls received by the police and 4,300 vehicles checked.
Officers even travelled to Spain to question a suspect.
Despite no clear sign of a breakthrough, Det Ch Insp Marjoram is confident the murderer will be found eventually.
He said: "The investigation team is totally committed to finding the person responsible, to find the person who killed Milly."
Two weeks ago it was revealed Antoni Imiela, who was given seven life sentences for a series of rapes in the South East at the start of March, was to be questioned over Milly's disappearance.
Det Ch Insp Marjoram said Imiela was one of about 40 people, not all convicts, being looked at closely by the police.
He said: "Because of the crimes committed by Imiela he is being looked at, but I stress he is not a suspect.
"We are looking at what he was doing on the 21 March 2002.
"Indications are that he was working up in London on that day, but we have to go beyond that as we cannot always rely on people's work records.
"We are still working on that and when we are done we will be interviewing him."
He said some of the 40 people had criminal backgrounds, but others were people who may have known Milly, although not necessarily relatives or family.
"All the way through we have looked at two hypotheses; that she could have been killed or abducted by someone she did not know, or she could have been picked up by someone she knew and unfortunately it led to her death.
Milly Dowler was on her way home from school when she went missing
"Since the day that Milly was first reported missing there has never been a let up in the investigation.
"Anyone of the people we are interviewing could be the person we are looking for.
"I would like to say we are very close to arresting somebody, but that would not be right.
"We have gone to the ends of the earth to find out who is responsible and we have committed huge resources to the investigation."
He said initially the number of officers involved was well over 100, but that took into account all the people involved in house to house inquiries.
Fifty officers are still working on the case in Guildford.
"We are determined to find who is responsible for Milly's death and we will not give up until we find the killer," said Mr Marjoram.
Anyone with information about the Milly Dowler case should contact Surrey Police or Crimestoppers.