German investigators' prime suspect in the disappearance of Madeleine McCann will be released from prison in a matter of weeks, local authorities have confirmed.

Christian Brückner, who is serving a sentence in northern Germany for a rape conviction, will be released by 17 September at the latest, the lead prosecutor investigating the toddler's disappearance told the BBC.

Hans Christian Wolters also said that he believed the 48-year-old German national was dangerous but that the current legal situation meant he must be released from prison without delay.

Brückner has never been charged with any crime in relation to Madeleine's disappearance and denies any involvement.

The then-three-year-old vanished from an apartment complex in Praia da Luz in the Algarve on 3 May 2007, sparking a Europe-wide investigation that has become one of the highest-profile missing persons cases.

Madeleine's parents had been dining with friends at a restaurant a short walk away while their daughter and her younger twin siblings were asleep in the ground-floor apartment.

They had checked in on the children periodically until her mother, Kate, discovered she was missing at around 22:00 local time.

The case remains unsolved, but German prosecutors have pointed to evidence suggesting Brückner may have been in the area when Madeleine disappeared.

Mr. Wolters stated that while he and other prosecutors did not believe they had enough evidence to formally charge Brückner in relation to the McCann case, their efforts would continue.

Brückner, who spent many years of his life in the Algarve, was a drifter, a petty criminal and a convicted sex offender. He has several previous convictions, including for sexually abusing children in 1994 and 2016.

Due to differences in legal systems, German authorities suspect Brückner of murder in relation to Madeleine McCann, while British police continue to treat her disappearance as a missing persons case.

Prosecutors are applying for restrictions to be placed on him when he is released, including fitting him with an ankle tag, as assessments have labeled him a danger to society.

Despite ongoing analysis of seized items from recent searches, no breakthroughs have emerged in the case over the past five years, but the investigation is not considered a failure.