The gun retrieved from a well drained by firefighters last week during fresh Madeleine McCann searches on the Algarve is a 6.35 calibre, well-placed sources said today. Further details emerged hours after German prosecutors described the co-operation with Portuguese police as “excellent and very constructive” as authorities in both countries continue to try to build up a case against suspect Christian Brueckner ahead of his scheduled release from prison in September.

The type of gun discovered during the three-day search operation last week near Brueckner’s former ramshackle cottage home close to the Algarve resort where Madeleine vanished on May 3 2007, has not yet been revealed. Typically, 6.35 calibre guns are small, pocket-sized, semi-automatic pistols used for self-defence or fun target shooting, but can be airguns.

Portuguese daily Correio da Manha reported yesterday it was unlikely to be a “lethal weapon” although tests are understood to be ongoing.

It has not yet been ruled out as a potential game-changer in the ‘race against time' to charge Brueckner over Madeleine’s disappearance before he finishes the seven-year prison sentence he is currently serving for the 2005 rape of an American OAP.

Another gun said to have been found during last week’s searches has been ruled out. It is believed to be more than 50 years old and has been described by Portuguese sources as a “rusting relic.”

The same well-placed sources confirmed yesterday forensic analysis of fragments of bones and adult clothing also unearthed last week would take place at a specialist police lab in Lisbon and not in Germany as initially reported.

No samples of any kind have been sent back to Germany despite reports to the contrary, the insiders said.

German forensic officers have been offered the opportunity of being present at the tests, although it was unclear today if they had accepted the invite.

They were shown some of the bones that were unearthed, thought to be animal bones, in a video-conferencing session but are said to have been “unable to come to any real conclusions about exactly what they were” via the screen.

German prosecutors said yesterday in their only official statement so far since wells, ruins and water tanks across a 120-acre area in Atalaia between the Algarve towns of Praia and Luz and Lagos were inspected: “The search operation conducted in Portugal last week has been completed as planned.

“No information can be provided at this time regarding the results of the investigation.

“Our sincere thanks go to all police officers involved in the search.

“The co-operation between the Portuguese police and the Federal Criminal Police Office was excellent and very constructive.

“We don’t want to say anymore at the moment.”

Luis Neves, the National Director of the Policia Judiciaria police force which in Portugal has been the lead police force in the hunt for Madeleine and whose officers worked along German counterparts at last week’s search, insisted last Friday it had “not been in vain” despite the apparent lack of results.

He said: “Nothing is in vain, not least because doors are being closed".

At the last Madeleine McCann search in Portugal just over two years ago, when the Arade Dam a 40-minute drive from Praia da Luz was combed, German police who requested the operation did take back home with them samples believed to be mainly soil samples.

The remote dam was described at the time as Brueckner’s “little paradise.”

The May 2023 dam searches were the first major searches in Portugal for Madeleine McCann in nine years following an earlier June 2014 operation when British police were given permission to do digs in Praia da Luz that involved sniffer dogs trained in detecting bodies and ground-penetrating radar.

Those Scotland Yard digs were linked to the leading UK police theory at the time Madeleine died during a break-in while her parents were eating tapas nearby with friends, and burglars dumped her body.

They also failed to produce any evidence pointing to the missing youngster’s whereabouts.

In a smaller operation in July 2020, Portuguese police and firefighters searched three wells for Madeleine’s body but failed to find any trace of her.

Last Friday, Correio da Manha claimed German prosecutors had refused to probe a couple suspected of running over Madeleine McCann in a drink-drive accident.

Portuguese authorities demanded an investigation into a British man and his German wife after his UK-based sister tipped off cops in 2018that  she thought he could be covering up a dark secret about Maddie’s disappearance, the newspaper reported.

But it said German authorities rejected a Portuguese request to use an undercover police officer with a fake identity to try to befriend the female suspect and firm up their suspicions that she was driving a car that hit Madeleine while under the influence of alcohol.

There has so far been no official response from German, Portuguese or UK police to the claims.

Convicted 48-year-old paedophile Brueckner denies any involvement in Madeleine's disappearance.

His earliest possible prison release date is September 17 - though his lawyer said he would have to pay £1,300 in outstanding fines from a series of motor offences to leave then.