LONDON (Reuters) – British and German police say a German child sex offender, currently in prison in Germany, is a prime suspect in the hunt for missing Madeleine McCann who vanished in Portugal 13 years ago while her family were on vacation.

Here are details about the main developments in the McCann case, one of Britain’s biggest unsolved crimes which attracted worldwide attention and a global hunt.

WHAT HAPPENED?

On May 3, 2007, Madeleine McCann, 3, vanished from her bedroom in the apartment her family were staying in at the Praia da Luz resort in Portugal while her parents, Kate and Gerry, ate with friends – known as the “Tapas 7” – at a nearby restaurant.

The apartment was broken into while Madeleine and her twin baby siblings were asleep, and local police concluded it was a kidnapping. The family voiced concern at what they called a slow initial police response and the failure to secure the crime scene.

In following days, the McCanns turned to the media to help locate their daughter, and the case attracted global attention with soccer stars David Beckham and Cristiano Ronaldo joining the appeals for information.

Author J.K. Rowling was among well-known figures to contribute towards a multi-million pound reward.

THE INVESTIGATION

The media focus on the case led to reported sightings of Madeleine across the globe. However, the early investigation by Portuguese police produced no major leads and the detectives began to focus attention on the parents themselves.

In September 2007, Gerry and Kate McCann were questioned by police as formal suspects. The following July, the Portuguese police dropped their investigation because of a lack of evidence and cleared the McCanns of any involvement.

The couple and their friends who were with them on the night Madeleine went missing successfully sued a number of British tabloids for libel for suggesting they were involved in their daughter’s disappearance.

In 2015, a Portuguese court also ordered a former Portuguese investigator involved in the initial inquiry to pay the McCanns damages for alleging in a book that the girl had died in an accident and the parents had covered it up.

A British man, whose mother’s house was close to the McCann’s apartment, also wins libel damages from 10 British newspapers after they accused him of being involved in Madeleine’s abduction.

In 2011, then British Prime Minister David Cameron orders a review by London police after being contacted by the McCanns.

The following year, detectives say they have identified 195 “investigative opportunities” and in 2013, the British police began their own investigation – Operation Grange – saying they have identified 38 potential suspects.

Later that year, they release an e-fit image of a number of men, including one of an unidentified suspect they particularly wanted to trace. Soon after, Portuguese prosecutors ordered the case to be reopened by local police.

The new inquiry leads Portuguese police to interview four suspects, but they are later cleared of any involvement, and a search by British detectives of wasteland near Praia da Luz also failed to provide a breakthrough.

The London detectives later suggested Madeleine might have been one of the victims of a series of sexual assaults on British children in Portugal, probably carried out by a single offender, between 2004 and 2010.

But in 2017, marking a decade since she disappeared, detectives say they might never solve the case despite still following critical lines of inquiry, although the British government has continued to fund the investigation.

On Wednesday, British and German police said they had identified a new suspect in the case, a 43-year-old German man. The suspect, who was not publicly named, lived in the Algarve between 1995 and 2007 and burgled hotels and holiday flats as well as trading drugs.