No clues, no leads as the hunt for Milly runs out

When the police first received a call from the worried parents of 14-year-old Milly Dowler, they were confident of finding the missing girl.

The case appeared to be relatively straightforward – a teenager on her way home from school disappears as she walks through a busy Surrey commuter town. Surely there would be eyewitnesses and photographs of the girl on surveillance cameras?

But more than three months after she vanished, the police are no nearer to finding Milly – and unless fresh appeals for help are successful they are expected to begin scaling down the inquiry.

Surrey Police was first alerted at 7.12pm on 21 March by Milly's father, who had grown increasingly alarmed at his daughter's absence.

She was last seen at 4.05pm as she set out from Walton station to walk home, having already taken a train from Heathside School in Weybridge. She had telephoned her father 18 minutes earlier on a friend's mobile to say she was running late after stopping at a café for some chips.

By about 9pm the same evening Surrey Police had searched Milly's home and begun to organise the recovery of surveillance cameras on her route through Walton-on-Thames. Specialist search officers, search dogs and a helicopter were deployed that evening to search the area.

At first the police concentrated on the likelihood that Milly had been abducted by a man in a car but, when no witnesses came forward to report seeing a kidnap and the cameras came up blank, the investigation began to concentrate on whether the missing girl had run away, possibly with someone she had met while using an internet chatroom.

The police inquiry was greatly helped by the nationwide publicity the case generated. While dozens of people go missing every week, most cases can expect at best to receive a few paragraphs and a photograph in their local paper.

But the Amanda – everyone calls her Milly – Dowler case had the magic ingredients that make it an irresistible story for the press, television and radio.

She was a young, attractive white girl living in a wealthy town in Surrey with professional and articulate parents, Bob, a 50-year-old IT consultant, and Sally, a 43-year-old teacher – elements that almost every editor could identify with. In addition, the teenager disappeared on her way home from school during daylight, every parent's nightmare.

For television there was the added attraction of video footage showing a vibrant, pretty girl, at play at home.

The media response was overwhelming. Emotional appeals by Milly's parents and her 16-year-old sister, Gemma, a television reconstruction, and pleas from celebrities including the pop star Will Young, have led to more than 3,200 calls from the public.

Meanwhile, Surrey Police was pouring resources into the case. While still classified as a missing persons inquiry, it was treated as a murder hunt in all but name. A squad of 100 officers was set up and within the first week more than 140 items were removed from the family home. More than 100 friends and family members have been contacted, and have told police that Milly had no reason to leave home and that running away would have been out of character.

The day after her disappearance, the police downloaded files from the girl's home computer and forensic scientists began tracing a possible internet stalker. Experts were also brought in to try to trace Milly's mobile phone.

During the next few days, five specialist search officers made fingertip searches of the Dowler family home and garden. Nearly 100 items have been analysed for possible clues. In addition, specialist officers searched more than 260 sites within a five-mile radius of the family home.

Milly's parents have had several false alarms. A body found in the Thames turned out to be that of a missing elderly woman; a man arrested three miles from Walton in Chertsey, Surrey, in connection with the teenager's disappearance was released without charge, and a prisoner at Belmarsh jail in south-east London has also been questioned.

As the weeks have gone by without a breakthrough the police have begun to look around for less obvious answers, including the possibility that Milly killed herself, or had been the victim of a predatory paedophile operating in the South-east. The lack of a witness or any hard scientific evidence added to the officers' growing feeling of frustration.

And as time went on, the bill for the inquiry has continued to rise. With an annual budget of £128.5m and ever-increasing demands of the police's resources, the Surrey Chief Constable, Denis O'Connor, and his deputies are well aware that they need to be able to justify every pound they spend.

Surrey Police has admitted it has "employed unprecedented resources to work on the investigation team". While the force has refused to comment on the overall cost of the inquiry, the figure is understood to have already gone well above £1m.

As the inquiry struggled to make a breakthrough, Mr O'Connor called in a team from the neighbouring Sussex force to review the case to check whether any clues had been missed.

Two weeks ago a Sunday newspaper reported that the review had concluded that the inquiry was "chaotic and rudderless". Surrey Police responded with fury, claiming that the review concluded: "This is a well run inquiry with an immense amount of effort by Surrey Police."

Meanwhile Detective Chief Inspector Brian Majoram, an expert on paedophiles who helped to bring the pop impresario Jonathan King to trial, has been brought in to run the day-to-day operations.

As the case goes into its fourth month, the Dowler family lives with the constant trauma of not knowing what has happened to Milly.

Speaking on their daughter's 14th birthday last month, Mr and Mrs Dowler said: "It would have been inconceivable if, when Milly first went missing, someone had said that we still wouldn't know what had happened to her by her birthday, especially given all the effort everyone has put in."

As Surrey Police prepares another push to crack the case, the Dowlers must be praying for a breakthrough.