Drifting around the German city of Kiel, Christian Brueckner was in a typically belligerent mood last week, sneering at claims that he might be extradited to the UK and finally made to answer questions about Madeleine McCann.

Moving between cheap hotels, homeless shelters and tents – at one stage he is even said to have been living in a shipping container – the convicted sex offender strikes fear and fury into the hearts of those who recognise the 48-year-old’s arrogant, pock-marked face.

Mothers in Dietrichsdorf, the working-class district of the port city in northern Germany where Brueckner lives, are so terrified by his presence that they have formed a campaign group to keep tabs on his movements.

Some of them, The Mail on Sunday was told, are no longer allowing their children to go out alone in case they cross paths with a man who, by his own account, is now ‘the most known bad person in the world’.

The elderly, whom he has also targeted in the past, are also keeping their doors locked.

‘He is a rapist but he walks around here as if he has never done anything,’ says one campaigner. ‘He is often out alone. Germany protects him far too much. The government has failed completely.’

For the past six years, Brueckner has been the only person connected to the 2007 disappearance of three-year-old Madeleine in the Algarve, Portugal.

But while German police named him as their prime suspect in 2020 – stating they believe that Brueckner abducted and murdered the British girl – no charges have been brought against the convicted sex offender. In fact, so unrepentant is he that last week he sent messages to the MoS saying that he has become a ‘vogelfrei’ – an outlaw –and complaining: ‘There is no law for me. I feel like anybody can do anything with me.’

As Madeleine’s parents Kate and Gerry and twin siblings Sean and Amelie, 21, marked the 19th anniversary of her disappearance in a prayer vigil in Rothley village, Leicestershire, last week, Scotland Yard was weighing its options. Namely, whether it has enough evidence to apply for the German national’s extradition in a desperate attempt to get him to stand trial at the Old Bailey.

Such a move was quickly dismissed by German government sources who say criminal suspects cannot be extradited to non-EU countries because of strict rules put in place after the end of the Second World War.

A source close to Brueckner’s legal team also told the MoS that ‘the chances of this happening are non-existent’. They added: ‘If the UK authorities have any evidence and are so sure of it, why don’t they share it with the Germans so they can look at it and press their own charges?’

Brueckner is said to have laughed off the idea of being dragged into a British courtroom.

Another source close to the paedophile, whose offences against children stretch back to the mid-1990s, said: ‘He has seen the news and is unfazed by it. He’s very confident this won’t be going anywhere, but then he has always been an arrogant and self-assured man.’

But with pressure mounting on German and British police to bring him to trial before the 20th anniversary of Madeleine’s disappearance next May, there are signs that this agonisingly slow investigation may finally be gathering pace.

Detectives from both countries are said to be evaluating their evidence with a view to bringing charges against Brueckner, who was living near Praia da Luz, from where Madeleine went missing.

Phone records are said to place him near the Ocean Club where she was staying with her family around the time she vanished.

But despite claims that Scotland Yard is considering trying to extradite him to the UK, it is understood British police would prefer to see him brought to justice in his native Germany. Detectives in both countries are sharing what they know in the hope that, between them, there is enough information to bring abduction and murder charges.

Meanwhile the serial paedophile, who has been linked to four other child murders across Europe, is due to be hauled back to court in Germany over an alleged fight with a British man said to have punched him twice in the face.

Brueckner, say German sources, was arrested along with the Briton on suspicion of ‘mutual assault’, an offence under German law where both parties are regarded as perpetrator and victim.

It is understood the Briton was walking with two dogs when he challenged Brueckner for riding his bike on a path for pedestrians. It is unclear if he recognised him as the Madeleine suspect. Brueckner is alleged to have thrown down his bike and become aggressive.

The incident is likely to see Brueckner back in court, after having been released from a seven-year prison sentence in Germany last September for the 2005 rape of a 72-year-old American tourist in Praia da Luz.

He is due back, anyway, early next month to face accusations of driving without a licence and having incorrect licence plates – and also to face charges related to an altercation with a guard while he was locked up at Oldenburg prison, near Bremen.

These petty crimes aside, what detectives want now is to see charges brought against him over Madeleine’s disappearance.

The MoS has been told exclusively that jobless Brueckner was able to refuse an interview with Scotland Yard detectives last September after a stand-off during which he exercised his constitutional rights under German law. 

An ‘International Letter of Request’ for an interview was sent from the Crown Prosecution Service to the German prosecutor. Detectives were told, however, that if they want to speak to Brueckner, they would first have to reveal the evidence they had against him – something they were not prepared to do.

The request was subsequently rebutted by the courts.

According to Brueckner’s lawyer Friedrich Fulscher, he ‘was not informed on what specific facts the alleged suspicions were based’. Access to files was denied to British authorities.

Brueckner’s name first cropped up in connection with Madeleine’s disappearance in 2013, but it wasn’t until 2020, after a 2017 TV appeal yielded important leads, that German investigators named him as someone they were investigating and made the claim that they believed Madeleine was dead.

They have never revealed the key piece of evidence which has led them to that conclusion.

There is plenty of circumstantial evidence against Brueckner.

A burglar with a history of breaking into holiday apartments and hotels on the Algarve where he was living at the time, he also has a string of convictions for sex offences, thefts and drug dealing.

His mobile phone was reportedly traced to the Praia da Luz area on the night Madeleine disappeared from an apartment as the twins slept nearby and her parents dined with friends 180 yards away. Brueckner transferred ownership of one of his vehicles shortly after her disappearance.

A former criminal associate Helge Busching, who was living in the Algarve in 2007, has also pointed a finger at him, claiming Brueckner told him that it was ‘strange Madeleine didn’t scream’ when they discussed the case at a festival in Portugal in 2008. Busching believes Brueckner planned to burgle the McCanns’ apartment but decided to take Madeleine instead.

‘That man is evil, he’s bad and he deserves to stay behind bars,’ he told the Daily Mail during an exclusive interview last year.

Brueckner, who was declared a formal suspect, or arguido, by Portuguese police in 2022, denies any involvement in Madeleine’s disappearance. And while searches of properties linked to him have found hard drives and USB sticks containing child abuse images, there is apparently no forensic evidence to link him to the case and, despite multiple searches in Portugal, not enough to charge him.

In 2024 he stood trial for unrelated sex offences, including three charges of aggravated rape and two charges of child sex abuse – crimes that German police hoped would keep him in prison while they continued their investigations into Madeleine’s case.

But in October that year, in a decision that caused widespread outrage across Germany, a court in Braunschweig, near Hanover, acquitted him on all counts, saying there was insufficient evidence.

Last September, not long after his release from prison, he turned up at the German public prosecutor’s office in Braunschweig in an act of protest, saying that he wanted ‘his life back’.

In letters sent from prison in 2022 to the Daily Mail, he wrote that the police ‘had not even one proof that I was involved with the McCann case. And they still don’t have it. I know why. Because they have no hairs or anything from Maddie what means [sic] that nobody can put anything like that into my stuff to find it’.

He added confidently that ‘there will never be a trial’ and ‘my self-confidence and self-control was never at a higher level’.

Since his release he has flitted between several cities in northern Germany, including Bremen, Neumunster and Braunschweig, provoking outrage and fear in each because of his hideous criminal past stretching back to his teens. He is frequently being forced to move on.

Despite receiving around £480 a month in state benefits, he is regularly evicted from hotels and hostels, and was banned from one supermarket following complaints from customers who instantly recognised him.

He created havoc in a nightclub last year after several women noticed him.

In the past, when asked if he is responsible for Madeleine’s disappearance, he has smirked. But while trying to buy an untraceable phone last year, he is said to have bragged to one shopkeeper that he ‘could bring the scandal of the century to an end’.

Early last month he returned to Kiel by bike, provoking more outrage among residents who are furious that a man placed by criminologists in the ‘top one per cent’ of the world’s most dangerous criminals is allowed to walk free in their midst.

One woman in the city who has campaigned against his presence told the MoS that residents remain frightened. ‘I want protection for the victims and future victims,’ she said, giving her name as Annika.

Operation Grange, the Metropolitan Police’s investigation into Madeleine’s disappearance, has cost taxpayers more than £13.3 million, with specialist officers travelling to Portugal to search scrubland, ruined buildings, wells and drainage areas around Praia da Luz. Currently consisting of three officers and one part-time member of police staff, the team has been granted funding to continue the investigation for another year, but their annual budget has been cut from £108,000 to £86,000.

Is it possible, then, that nearly two decades on, a decision about charging Brueckner is finally on the horizon?

Last week’s prayer vigil in Rothley was a stark reminder that at the heart of this international red tape lies the agony faced by Madeleine’s family.

The rare appearance in public made by university students Sean and Amelie, who were two years old when their sister disappeared and recently turned 21, was a bitter-sweet reminder of the young woman Madeleine would be now and the future she could have enjoyed with her family.

Brueckner is still under active police surveillance and has to report to a probation officer monthly. He will also wear an ankle tag for the next five years.

He is often seen out and about on his bike, cycling close to the harbour in Kiel in an area packed with schools, green spaces and children’s playgrounds.

Ironically he is paranoid about being attacked.

Last month he told a Daily Mail journalist that he was being followed by unknown men in cars. In one text message he wrote that he feared he ‘might be dead soon’.

For his known victims, that day might not come soon enough.

But for those who believe Brueckner still holds the key to unravelling the world’s most infamous missing child case, the only thing they want is to see him in court facing justice.

Additional reporting: Rob Hyde

• To get a free exclusive article on what has happened to Fred and Rosemary West's children, more than 30 years after 'house of horrors' was found, sign up to our newsletter HERE  
• What kind of cases do you want to read more about? Let us know at: crimedesk@dailymail.co.uk