Authorities say Madeleine McCann is presumed dead.

BERLIN —
On May 3, 2007 during a family holiday in the Algarve region in the South of Portugal, three-year-old Madeleine McCann disappeared. Now, 13 years later, a lead suspect has been identified: a 43-year old German male who authorities have not yet named. The announcement is a step towards unraveling what remains one of Britain’s most famous unsolved crimes.

Prosecutors believe she is dead and German authorities are treating her disappearance as a murder investigation. The girl’s parents, Kate and Gerry have called the news “the biggest lead in the case in 13 years” a spokesperson for the couple, Clarence Mitchell, told Sky News.

“[Madeleine’s parents] are realistic, they simply want to know what happened to their daughter” he added.

The abduction spurred a massive manhunt around Europe. Some notable names, including J.K.Rowling, contributed to a multi-million pound reward, while soccer star David Beckham publicly appealed to the public for information about her kidnapping. Yet the amount of money spent on the investigation, which until now had produced no lead suspect, had become a topic of debate in the U.K. press. The most recent investigation by Metropolitan Police in London which began in 2011 cost nearly $14 million, BBC reported.

The suspect is currently serving a long sentence in a German prison for sexually abusing children. During a press conference in Braunschweig, Germany, on Wednesday, the region where the suspect last held residence before moving to Portugal, authorities said he was a “sexual predator who had already been convicted of crimes against little girls” and had been sentenced to prison several times on related counts.

Between 1995 and 2007 the suspect had been living in the Algarve, at times out of a camper van from the 1980s. Authorities determined he had been living in a house near the Praia da Luz resort from which Madeleine disappeared one evening while her parents were at a nearby tapas bar with friends. At the time, local police concluded it was a kidnapping: a stranger had broken into the apartment while Madeleine, known as “Maddie” was sleeping, along with her twin sisters.

While living in Portugal, the suspect “pursued several odd jobs in the Lagos area, including in the catering trade. There are also indications that he may have made his living by committing crimes such as burglary theft in hotel complexes and holiday apartments, as well as drug trafficking.” The Braunschweig Federal Prosecutor’s Office wrote in a statement.

Now, authorities are turning to the public for help to crack the case and have offered a $25,000 reward (£20,000) for information leading to a conviction.

“As part of the investigation carried out by Germany’s criminal police, Britain’s Metropolitan Police and Portugal’s Policia Judiciaria at the request of the public prosecutor’s office in Braunschweig, we are now asking the public for help. A call for witnesses was published yesterday on the internet site of the German criminal police” said Braunschweig State Prosecutor, Hans Christian Wolters in Tuesday’s press conference.

Police are requesting information about two cell phone numbers, one of which belonged to a person whom police believe is a “highly significant witness.” They have released photos of two vehicles the suspect could have used during the time of the disappearance.

The first is a 1993 British Jaguar with German license plates and the second is a Westfalia campervan from the early 1980s which the suspect used in and around the area of Praia da Luz. “We believe he was living in this van for days, possibly weeks, and may have been using it on 3 May 2007.”