As the director of hit movies The Odyssey, Dunkirk and Interstellar, Christopher Nolan is well acquainted with telling dramatic stories.

But one little-known episode from his own family’s past was as dramatic as any Hollywood movie script – when his older brother was accused of having been the hitman behind a transcontinental gangland assassination.

In the legal fallout from the case, Christopher himself personally intervened to beg a judge to show his troubled brother mercy, never-before-seen documents reveal.

And in an extraordinary coincidence it was alleged that his ‘hitman’ brother used the codename ‘Oppenheimer’ – which 15 years later would be the title of the film for which Christopher won an Oscar for Best Picture, the Daily Mail can reveal for the first time.

Details of his heartfelt plea on behalf of his brother have emerged as Christopher is being tipped for numerous Oscars for The Odyssey, his hit adaptation of the epic ancient Greek poem by Homer.

The bizarre case unfolded 16 years ago when Christopher was already one of cinema’s most exciting emerging film talents – and now newly obtained documents shed new light on what happened as well as on the director’s close involvement with his brother’s bizarre legal case.

Matthew, 57, is the eldest of the three Nolan brothers but has led a very different life to Christopher, 56, and Jonathan, 50.

They were all born in London to dad Brendan, an advertising executive from Britain, and their mother Christina, who is American, meaning the brothers are all joint UK and US citizens.

Matthew (left) is the oldest of the Nolan brothers, followed by Christopher (centre) and Jonathan (right) – the trio are pictured at Matthew’s wedding

Matthew was wanted for aggravated kidnapping, use of a false document and aggravated homicide, in other words, murder

Christopher pictured at the 96th Annual Academy Awards after winning Best Picture for Oppenheimer

All three were educated at the elite Haileybury school in Hertfordshire, where fees are now £50,000 a year, but after that Christopher and Jonathan headed for Hollywood.

Christopher has since won two Oscars and a Golden Globe – so far – and has been internationally lauded for his films like Interstellar and his gritty reboot of the Batman franchise.

Jonathan meanwhile is an in-demand producer who has been nominated for an Academy Award for the 2000 movie Memento and helped to create the hit HBO series Westworld.

Matthew took an altogether different route and became a property developer in Chicago. But in the 2000s he ran into financial difficulties and in 2009 filed for bankruptcy, his life starting to fall apart.

What happened next was shocking: in March of that year a judge in Costa Rica signed off on an extradition request for Matthew related to the death of Robert Cohen, 63, a Florida accountant whose body was found in 2005 in the Central American country.

Matthew was wanted for aggravated kidnapping, use of a false document and – incredibly – aggravated homicide, in other words, murder.

According to the Costa Rican police, a wealthy gem trader named Robert Breska had ‘hired Matthew to kidnap and torture Cohen’ over a dispute involving a missing $7million’.

Mr Breska allegedly told Mr Cohen to meet Matthew in San Jose in Costa Rica, claiming he was a ‘multimillionaire’ and a member of the Oppenheimer jewel dynasty.

The allegations from the Costa Rican authorities, as detailed in Judge Mason’s summary, grew even darker from there.

They claimed that, on March 6, 2005, Matthew agreed with Luis Alonso Douglas Mejia, a Costa Rican man who was later convicted over the murder, to ‘execute the plan to kidnap the victim’.

The judge’s memorandum states that, in its extradition request, Costa Rica claimed that Matthew and Mejia carried out the kidnapping by ‘forcing Mr Cohen into Matthew’s car’.

The extradition request stated that Matthew ‘violently’ took Mr Cohen from the parking lot and prepared the plan to keep him ‘hidden in an isolated area of a solitary beach’.

The ‘mission’ was to end Mr Cohen’s life, the document stated.

An extradition request was put in for Matthew, related to the death of Robert Cohen, a Florida accountant, who is pictured with his daughter Alisha Cohen

But Judge Mason refused the extradition request on the charges of aggravated kidnapping and aggravated homicide, calling the evidence of Matthew’s involvement ‘unsupported and unsubstantiated’.

According to Judge Mason’s summary, there was ‘competent evidence’ that Matthew was with Mr Cohen at the moment he was kidnapped, including surveillance camera footage from a hotel where both men were staying.

There was also ‘competent evidence’ that the car Mr Cohen was driven away in was the Toyota 4Runner Matthew had hired.

‘What is lacking is evidence that Breska retained Matthew as a ‘hired killer,’ the judge wrote, ‘that Matthew planned to kidnap and murder Cohen, that Matthew was aware of, let alone ordered, Mejia’s actions, or that Matthew engaged in any violent act.’

The judge did however approve the extradition request based on use of a false document, in this case for using a fake British passport to open a bank account in Costa Rica.

The British embassy in Costa Rica verified that the passport, which was in the name of ‘Matthew Francis McCall’, was fraudulent, the document states.

All of that led to Matthew being arrested while attending a hearing in his personal bankruptcy case, and began the next bizarre chapter in his story: his attempt to break out of prison.

He was indicted in October 2009 on five counts related to materials found in his cell at the Metropolitan Correctional Centre (MCC) in Chicago, a troubled and overcrowded skyscraper with a history of complaints about the conditions.

Court documents state that prison guards ‘recovered approximately 31 feet of braided roping material, a similarly braided harness, a metal clip from a pen cap, and a broken piece of a razor blade hidden in the defendant’s bar of soap’.

Officers at the MCC were ‘successful in opening a locked pair of handcuffs with the metal clip,’ the documents stated.

Images of the materials were included in the court file and show a long piece of rope and the metal clip next to a ruler.

The plot appears to have been fanciful: the MCC is a 28-storey skyscraper which has never seen an escape before.

It is located in a busy area of Chicago, meaning any escape through a window would be highly visible, and the windows themselves are narrow slits.

According to court papers, Matthew was accused of using code words to talk to another person about his escape, using terms like ‘beach party’ to describe it.

In one note to the other inmate at the MCC, referred to as ‘Individual B’, Matthew alluded to his extradition in Costa Rica.

Jonathan (right), pictured alongside his brother Christopher (left), is an in-demand producer who has been nominated for an Academy Award for the 2000 movie Memento

He said: ‘You are right about my situation. If they get me down to the Southern Cross, I won’t be coming back.’

In another note to Individual B, Matthew appeared to talk about rappelling out of a window of the MCC and have somebody else pick him up.

He said: ‘My thought was tape the window, crack, mount rope w/ rope sleeve and rope bag . . . rappel to street + friends . . . . trigger man runs the op from parking garage.’

The prosecution filing said that Matthew also bragged about being able to get out of his handcuffs in 15 seconds.

And it was at this point that iconic director Christopher took a direct involvement in his brother’s legal troubles.

The black sheep brother’s lawyers pleaded for leniency and included letters to the court from his wife, children and Christopher, whose hit movie Inception was due to come out a month later.

In his letter, Christopher said that the situation was ‘heartbreaking’ and that missing the death of their father from cancer while in prison had been ‘awful’ for Matthew.

‘I believe that the shame and hardship his incarceration has brought [him] means that his punishment has already been substantial,’ Christopher wrote.

Dated June 28, 2010, Christopher’s letter said it was a ‘mystery and a shock’ why his brother was in such a situation.

He said that during his time at school, having an older brother at the same establishment was ‘no small source of comfort to’ given the ‘Darwinian environment of an English Catholic boarding school’.

Christopher wrote: ‘My brother supported me during this time with a loyalty that I have to believe would still characterise his attitude towards helping those who might need him.

‘He looked out for me without regard for himself, and I believe this suggests the depth of his commitment to family.’

While Matthew was in prison their father ‘lost his battle with cancer’, Christopher wrote.

He said: ‘My older brother was extremely close to our father, and whilst Matt’s situation was a confusing and heartbreaking one for my father to face, his love for his eldest son never wavered.

‘I am convinced that whatever else might be said about the effect of Matt’s imprisonment, his not being able to be present at our father’s death bed, not being able to say goodbye to the father he respected and loved so much, has been an awful punishment for him.’

Christopher said that the whole episode had ‘focused his [Matthew’s] mind on the important realities of his life’, meaning his family.

He wrote: ‘Knowing my brother’s commitment to family, I believe that the shame and hardship his incarceration has brought on them means that his punishment has already been substantial.

‘I believe that he would seize upon a second chance to show that he is a man capable of good on behalf of his wife and children, and good on behalf of society as a whole’.

Matthew eventually pleaded guilty to two counts related to the escape attempt.

He was jailed for 14 months but given he had already been in prison for that time, he was released and given a two-year period of supervised release.

It seems Matthew was quietly released and not extradited to Costa Rica because the only charge against him at the time was the use of a false passport. The other claims of murder and kidnapping were unproven.

A spokesman for Costa Rica’s Public Ministry, which deals with legal matters, said some time later: ‘This evidence that the US judge considered was insufficient to link Mr Nolan with the crimes committed against Mr Cohen, is the same evidence used to condemn Mr Mejia here in Costa Rica.’

Christopher is pictured with wife Emma Thomas while attending The Odyssey photocall at the IET Building in London in July

The following year, apparently so upset by his treatment while in prison, Matthew sued the US government for medical malpractice and sued his guards at MCC.

Both of the cases were dismissed.

Mr Cohen’s family did not respond to requests for comment: they have previously said that they hoped Matthew would face justice.

The Daily Mail also approached Matthew and Christopher Nolan and the authorities in Costa Rica.

Lawyers for Matthew have previously said he was innocent of all the charges against him and that he is sorry for the Cohen family’s loss.