Madeleine McCann’s parents have said they remain hopeful she will be found after the size of the detective team investigating her disappearance was scaled down.
Kate and Gerry McCann said they “fully understand” the decision by Scotland Yard to reduce the number of officers working on the case from 29 to four.
The Metropolitan Police said the vast majority of the work of Operation Grange, which was launched at the request of the government in 2011, has now been completed.
However, the force insisted the inquiry has not reached a conclusion, with the team now following a small number of “focused lines of investigation”.
It was also revealed that more than 60 “persons of interest” have been investigated , 650 sex offenders “considered” and 8,685 reports of potential sightings of Madeleine probed.
Madeleine was three when she went missing from the family’s holiday apartment in Portugal’s Algarve on 3 May 2007, triggering one of the most high-profile missing persons investigations of all time.
Her parents said: “We would like to thank all the staff from Operation Grange for the meticulous and painstaking work that they have carried out over the last four and a half years. The scale and difficulty of their task has never been in doubt.
“We are reassured that the investigation to find Madeleine has been significantly progressed and the [Met] has a much clearer picture of the events in Praia da Luz leading up to Madeleine’s abduction in 2007.
“Given that the review phase of the investigation is essentially completed, we fully understand the reasons why the team is being reduced.
“Whilst we do not know what happened to Madeleine, we remain hopeful that she may still be found given the ongoing lines of inquiry.”
Announcing the “new structure”, Scotland Yard disclosed that more than 40,000 documents have been collated as police brought all of the material relating to the case – from UK and foreign police, as well as private investigators – together for the first time.
Once this work was completed, the review became a full investigation in July 2012, and since then officers have taken 1,338 statements and collected 1,027 exhibits.
Some 560 lines of inquiry were identified and more than 30 requests sent to countries asking for work to be undertaken. On average the team received 200 e-mails a week.
A Met spokesman said: “A team of four officers will continue to work solely on the Grange investigation.The inquiry has not reached a conclusion, there are still focused lines of investigation to be pursued.”