Madeleine McCann may have been among the victims of a series of sexual assaults on British children in Portugal, British police have said.
Police believe the assaults could have been carried out by a single offender around the time she went missing seven years ago.
Madeleine disappeared, aged three, from her room at the Praia da Luz holiday resort in the Algarve in May 2007 while her parents were dining with friends at a nearby restaurant.
Her disappearance led to a global search that gripped the world's media.
British and Portuguese police are investigating a string of cases of sexual assault or attempted sexual assault on British children between 2004 and 2010.
One assault, which was only reported to police following a public appeal for information in March, was on a ten-year-old girl at Praia da Luz itself two years before Madeleine disappeared.
"This offence now takes us into the resort and of course is very important in investigating Madeleine's disappearance," said Detective Chief Inspector Andy Redwood at a news conference in London.
Det Redwood said he believed all the assaults involved the same man breaking into holiday villas occupied by British families in the western Algarve region.
"There are features within these new crimes that make us absolutely confident that they are part of a series," he said. "We are looking at one offender."
Last month, police said some of the victims had given a similar description of the attacker as being tanned, unshaven, with dark, unkempt hair.
He spoke English with a foreign accent and two of the victims described him as wearing a distinctive burgundy top, with long sleeves and a white circle on the back.
Despite numerous reported sightings of Madeleine from Belgium and Spain to Morocco, France and Malta, and investigations stretching as far away as Australia, her fate remains a mystery.
Her parents were named as official suspects by Portuguese police four months after Madeleine's disappearance, but in 2008 they were cleared.
Portugal's public prosecutor later dropped the case, citing a lack of evidence.
London police launched a review of the case in 2011 and began their own investigation last July.