Madeleine McCann suspect Christian Brueckner could face up to five years behind bars after being accused of assaulting a British man.

The convicted rapist, 48, is said to have been arrested alongside the Brit on suspicion of 'mutual assault' following a fight in the city of Kiel, northern Germany.

A source close to Brueckner, however, claimed that he was 'attacked by a British person' before calling the police himself. 

The German was only released from prison in September after spending seven years behind bars for the rape of a pensioner. 

'The guy appeared in front of him together with two other people and a big dog,' the source told The Mirror. 

'He yelled at Brueckner and hit him in the face twice and that's it and then the police came and arrested him. Brueckner called the police. He was injured.'

Under German law, 'mutual assault' is brought where the suspect is both a perpetrator and a victim.  

News of the alleged fight comes on the same week it emerged that the Metropolitan Police are pushing for Brueckner to stand trial in Britain for the abduction and murder of McCann. 

The toddler vanished aged three while staying at a hotel with her parents in Praia da Luz, Portugal, in May 2007. 

But the case has never been solved, despite the paedophile being named as the prime suspect in McCann's disappearance by German police six years ago. 

Charges were not brought and Brueckner has always maintained his innocence, though officers at Scotland Yard are said to be pushing to see him charged before the end of the year.

The Met is confident it can present a strong enough case to the Crown Prosecution Service - but Brueckner's extradition could prove a stumbling block. 

Article 16 of the German constitution states that, with the exception of EU member states and international courts like The Hague, 'no German may be extradited to a foreign country'.

Before the UK left the EU, a German national could be automatically extradited to the UK under the European Arrest Warrant, which requires members of the EU to surrender suspected criminals to each other with little to no fuss.

As a result, extraditions from Germany to the UK have been 'generally precluded by German constitutional law' following Brexit.

Asked by The Telegraph whether Brexit has blocked the UK from holding suspects like Brueckner to account, a German government spokesperson said: 'Yes, that is the case.'

And, speaking exclusively to the Mail this week, Brueckner's team laughed off the notion that he could face trial on British shores. 

A source close to his legal team said: 'We have been here many times before, and nothing has ever happened; we are sure this attempt will go the same way.

'If the UK authorities have any evidence and if they are so sure of it, why don't they share with the Germans so that they can look at it and press their own charges.

'German law forbids German citizens from being extradited to another country; they can only be put on trial in Germany, so the chances of this happening are non-existent.'

Meanwhile, another source close to Brueckner said: 'He has seen the news and is aware of it. He's completely unfazed by it. As far as he is concerned, they have had years to bring a case against him and have failed.

'He's very confident this won't be going anywhere soon, but then again, he has always been an arrogant and self-assured man.' 

Brueckner was born Christian Fischer in Wurzburg, Bavaria, and took the name he uses now when he and his two brothers were adopted by Brigitte and Fritz Brueckner, after their troubled mother gave them up.

At the age of 15, whilst living with his adoptive parents who were physically abusive, he was convicted of his first crime - a burglary.

In 1994, two years after his conviction, Brueckner's adoptive parents put him in a children's home after Fritz was left seriously injured in an accident.

It was while there that he was found guilty of his first sex offence, abusing a child in the home when he was 17.

Before being caught, he went on to sexually abuse a nine-year-old.

He was sentenced to two years in prison for 'sexual abuse of a child, attempted sexual abuse of a child and performing sexual acts in front of a child.'

But shortly afterwards, he travelled to Portugal, where he found jobbing work in hotels and garages before eventually being tracked down by police and extradited to Germany.

After serving his sentence, he returned to Portugal and in 2004 he was said to have raped Irish tour guide Hazel Behan at her apartment in Praia da Rocha on the Algarve coast - close to where Madeleine vanished three years later.

In 2005, he raped 72-year-old American woman, Diana Menkes, who was living in the Algarve and has since died.

In 2007, the same year Madeleine went missing, Brueckner left Portugal and didn't return for nine years, instead basing himself in Germany where his offending 'spiralled'.

Mobile data revealed that the 48-year-old's phone had been in Praia da Luz shortly before Madeleine vanished.

Brueckner was also said to have partially confessed to the crime in 2008, according to police statements, by telling a friend that 'she did not scream'.

Scotland Yard had submitted a request to interview the rapist prior to his release in September, but he refused.

The Met's investigation is part of Operation Grange, which began in 2011 following a Home Office request for a review of the case. At that point, Madeleine had been missing for four years. 

Kate and Gerry McCann, Maddy's parents, joined a prayer vigil in Leicestershire on Sunday to commemorate the 19th anniversary of her disappearance.

The parents did not address the 50-strong crowd outside their home in Rothley but looked pained as prayers were said for Madeleine.

After the brief 20-minute service Kate, wearing dark casual trousers with a puffer jacket, was seen smiling as she hugged and chatted to locals.

The family of four later walked away from the event to their nearby home.

In a new post on social media Kate and Gerry wrote: 'Nineteen years. The search goes on to find our Madeleine, to achieve some justice, to make the world that bit safer.'

They added on the official Find Madeleine Facebook page: 'We remain very grateful for all our support - from friends and family, people we know and those we don't - and from the police and authorities for their continued determination and effort. Thank you.⁣

'For Madeleine, who we love and miss every day, we will never give up. Kate, Gerry and family.'

A spokesman for the Met said: 'The Met’s investigation into the disappearance of Madeleine McCann has been active since 2011. A dedicated team continues to examine the events of the evening of 3 May 2007 in Praia da Luz, while supporting and updating Madeleine’s family.

'As part of ongoing enquiries, we remain in close working discussion with policing colleagues in Germany and Portugal. We will continue to pursue any viable lines of enquiry.'