The most high-profile suspect in Madeleine McCann’s disappearance is set for a return to jail after verbally abusing a prison officer.

Christian Brueckner, who several police forces across Europe have named as a suspect in the four-year-old’s disappearance in 2007, was serving a seven-year sentence for an unrelated rape case when he called one of the prison guards “son of a b**** in October 2023, according to German outlet Bild.

In December 2024, Brueckner was sentenced by Oldenburg District Court to six weeks in prison, a sentence which was set to be activated on Monday with a court reportedly prepared to throw out his appeal.

But after the 49-year-old’s lawyer called in sick, the case will now be delayed until autumn, meaning Brueckner will remain free, The Sun reported.

“Maddie prosecutors know as long as he is free there is a chance he will flee ­the country and disappear — and take any hopes of the case making it to court with him,” one source close to the case in Germany told the paper.

Brueckner has never been charged with any crime in relation to the McCann case. He denies any involvement.

Brueckner’s sentencing came after he filed a complaint against two guards in Oldenburg prison, where he served part of his sentence for the 2005 rape of a 72-year-old American woman in Praia da Luz, Portugal.

The convicted paedophile and rapist alleged that prison officers had kept him held in solitary confinement for too long and called two of the guards “torturers”, but the investigation into this complaint was closed.

Afterwards, the two officers filed a complaint against Brueckner for verbal assaults. Another guard also filed a complaint which accused the German national of calling him a “son of a b**** in October 2023. The Oldenburg public prosecutor’s office filed charges following an investigation.

Brueckner was sentenced to six weeks in prison by Oldenburg District Court in December 2024, after which he launched an appeal - which was reportedly due to be rejected.

In May 2025, Brueckner was sentenced to even more prison time for verbal abuse in Lehrte District Court at the Sehnde jail in Germany’s northern Hanover region. According to the charges, he insulted a senior prison officer by calling her a “joke”.

The 46-year-old officer said, according to Bild: “He was brought in to express his views and ideas on the execution of his sentence and his rehabilitation. Mr. Brückner was provocative and hostile from the start. He accused me of being responsible for his torture, claiming he was being housed in inhumane conditions.”

Brueckner then called her a “clueless joke”, she said, adding: “These remarks violated my honor.”

In a letter, the convict said he doesn’t know “what possessed me on that beautiful sunny day”, and defense lawyer Philipp Marquort said his outbursts were an allowable expression of opinion.

He was sentenced to a one-month suspended prison sentence.

Meanwhile, UK police are upping their efforts to bring the German rapist to trial in the UK in connection with the abduction and murder of Madeleine McCann.

According to reports in The Telegraph from May, senior officers are pushing to see Brueckner charged before the 20th anniversary of Madeleine’s disappearance next year.

Despite Madeleine’s case officially being a missing persons investigation, a small team of officers are building a file of evidence for the CPS in relation to her suspected abduction and murder, the newspaper reports. However, the force could face difficulties bringing the suspect to the UK, because the German constitution prevents the extradition of its citizens to non-EU countries.

But Article 16 of the German constitution means that Britain could face a diplomatic and legal battle if the Met tries to bring Brueckner to the UK.