For 18 years and counting I have failed Krishna Maharaj at every step in the American justice system. Kris’s is one of several hundred capital cases I have done over the years, but I doubt there is any other that has taken more out of me. Partly it is because we have a very close connection. He’s British. Once, when Kris was very wealthy (a self-made millionaire) and I was about 12 years old (living in Newmarket), he bought two racehorses off my father, long before both of them lost their businesses. I’ve known Kris’s wife, Marita, for many years, and often stay with her when I pass through south Florida on my way to Guantanamo Bay.

On 1 December 1987, Judge Harold Solomon accepted a Florida jury’s recommendation and ordered that Kris Maharaj should be taken up to the state penitentiary and executed with 2,400 volts of electricity poured through his brain, “And may God have mercy on your soul.”

Kris was convicted of the murder of Derrick Moo Young, 53, whom he had known for many years, along with the man’s 23-year-old son, Duane. It was a sensational crime, committed in October 1986 in Room 1215 of the DuPont Plaza Hotel in downtown Miami. On the face of it, when I first read the transcript of the trial, the prosecution case seemed strong. The victims were, the jury heard, innocent businessmen on a very limited income of about £15,000 a year. Kris had a motive: he was convinced the Moo Youngs had embezzled money from him, and that Derrick had embarked on a very public campaign to smear his name in a local tabloid, the Caribbean Echo.

The lead detective on the case, John Buhr­master, said that Kris had denied ever being in Room 1215, or ever owning a pistol. Yet Kris’s fingerprints were found all over the hotel room and he was shown to have bought a 9mm Smith & Wesson some months earlier, so he had to be lying. And a witness by the name of Neville Butler had, the judge was told, passed a lie-detector test with respect to his testimony: he had been present, watching, as Kris shot Derrick several times, and then executed Duane with a single bullet to the back of the head.

I took Kris’s case on in 1994. That may be a long time ago, but by then he’d already faced electrocution for seven years. He had watched as 16 other men had been led away to be killed, including Jesse Tafero, whose mother used to ride up for visits with Marita. Jesse insisted on his innocence – his co-defendant Sonia Jacobs was later exonerated and now lives in Eire. The flames flickered around Jesse’s head like a halo in 1990 as the electric chair malfunctioned. Kris was left sitting in his cell, imagining a similar fate of his own.

When I started working on his case, I had to give my new client the benefit of the doubt and take his claims of innocence seriously, or there would have been no point in his having a lawyer. But I never thought that justice could disintegrate quite as it had for Kris.

First, there was the matter of legal process. Before trial, Kris claimed that the trial judge, Howard Gross, had attempted to solicit a bribe of $50,000 from him: pay up and things would go well. Perhaps unwisely, as it transpired, Kris spurned the demand out of hand. The judge was taken off the case on the third day of Kris’s trial and replaced. The jury never knew it, but Judge Gross (known to his friends as “Howie the Mouse” for his rodent features) had been arrested that morning for taking bribes in another case. He was later disbarred.

The trial just ploughed onwards. If Gross was suitably named – given his apparent venality – the new judge was not: Harold Solomon could hardly be described as wise. When I asserted Kris’s right to see the prosecution files under the Freedom of Information Act, I found that this new judge had met secretly with the pro­secutors, asking them to write up an order sentencing Kris to death even before evidence for mercy had been presented.

And so it went on. Later, yet another judge, Leonard Glick, secretly told the prosecutors to write an order refusing Kris a hearing on new evidence casting doubt on his conviction. Glick also failed to disclose that he had been the prosecutors’ supervisor at the time of the first trial. Kris was finding it difficult to find a judge who would hear his case fairly. But was he telling me the truth when he insisted, the first time I met him, that he had nothing to do with the Moo Young murders?

Pretty soon it became clear to me that he was. First, I found the result of a lie-detector test taken by the prosecution’s star witness, Neville Butler, in the police file. It turned out that Butler had failed the polygraph. Kris, on the other hand, had passed his. Whatever the reliability of such a test, there were many other reasons to doubt Butler – his story just did not add up, and changed so many times that I was left with the clear impression that he was hiding a great deal, and most especially his own involvement in the murder.

I wish I could say I was surprised that Detective Buhrmaster misrepresented what Kris told him on the night of his arrest, but I’m afraid I’ve seen too much of that. In New Orleans, even officers have called it testi-lying when a policeman takes the stand. It turns out that Miami police were no strangers to the practice. Kris could not have carried out the murder with his Smith & Wesson, because the investigating detective’s notes (hidden from the defence, of course) corroborated Kris’s statement to me: the only pistol he had ever owned had been stolen from him months before the crime. And the detective had not told the truth about the fingerprints, either: his own partner described under oath how Kris explained that he had in fact been in the hotel room that day – Butler had lured him there in the morning on the pretext of a business meeting. He was then framed to look like the real killer.

But the biggest shock came with regard to the Moo Youngs. The detective told the defence, pre-trial, that the briefcase the two men were carrying when they were murdered had been returned to the family, yet I found a copy of its contents in the police file. The documents in
it were astonishing. First, it seemed, they had been trying to buy some jewels from a California “church” for $94m. Next, they were looking to purchase a bank in Panama (then led by Manuel Noriega) for $600m. And finally, there were letters from the Moo Youngs offering loans around the Caribbean to the tune of $5bn.

It all began to fall into place. In the mid-1980s, there was only one source from which that kind of loot could come – indeed, three of the five richest people in the world came from the same country, Colombia. Detective Buhrmaster had shown no interest in Jaime Vallejo Mejia, the man occupying the room across the hall from the murder scene; the policeman said he had peered through the door and the occupant “seemed legit”. Had Buhrmaster done a simple criminal records check on Mejia, he would
have learned that the man came from Pereira, Colombia, and was wanted for carrying $40m in cash to Switzerland. I was amused to discover that Pereira was “twinned” with Miami. I wondered whether the Miami councillors had been high on cocaine when they voted to establish the link.

It was obvious that the Moo Youngs were trying to launder drug cartels’ money. A close analysis of the documents showed they were trying to skim 1 per cent off the top – and 1 per cent of $5bn is $50m. You could get killed for looking strangely at a drug lord; stealing that kind of money guaranteed a death certificate.

The evidence exonerating Kris went on and on. There were six alibi witnesses who could place Kris in Fort Lauderdale, miles away, at the time of the murders. Ultimately, because he did not commit the crime, I came to know much more about the case than he did.

Kris’s case has stayed with me because he is so patently innocent, yet nobody seems to want to listen. It has been one of the most dissonant experiences in my life to be as certain of the innocence of someone as a lawyer can ever be, while the political and judicial might of the US continues to insist that he is guilty beyond a reasonable doubt and should pay the price.

How could this be? It’s not solely because the judges are corrupt. As I sat glumly wondering how I could have failed him for so long, it became clear to me: to err is human, but the US justice system is structured to make mistakes.

It all begins with the innocent defendant. He is the most useless person a criminal defence lawyer can ever have for a client. Not only can he tell you nothing about the crime – “I don’t know who did it, I wasn’t there,” says Kris – but he was unwilling to spend the time and money to ensure that he got a fair trial. He knows (100 per cent) that he is innocent, so how could 12 jurors possibly find him guilty beyond a reasonable doubt? Why does the defence need time for investigation? Why pay for experts? Why not go to trial tomorrow?

Justice depends on having jurors who really will give the accused person the benefit of the doubt. Over the years, I have conducted an
ad-hoc survey of what that means and have learned that the average judge (let alone lay juror) thinks that proof beyond a reasonable doubt indicates only that you have to be a little over 80 per cent sure he is guilty. In effect, they are aiming to be wrong one time in five. With 3,000 Americans on death row, they are shooting to execute 600 innocent people. If you aim low, you usually miss.

Who is to say that jurors do better than judges, particularly when, in a capital trial, it is a hanging jury? Citizens are excluded from service in a capital trial unless they promise they are willing to vote to execute the man on trial if he is found guilty. Consider what this means – if you have a problem with the death penalty, if you don’t feel you have the right to order the death of another human being, then you are automatically disqualified.

And what of the defence lawyer? Surely we agree that a capital trial, where life is at stake, calls for the best advocates that the law can provide. A corporation may pay $1,000 an hour for a lawyer – sipping a cup of coffee with your corporate attorney can cost you hundreds of dollars. But someone without money, who is accused of a capital crime, has to take a public defender who may be paid little more than $1,000 for the whole case. You get what you pay for. Often the death penalty is imposed not for the worst crime, but for the worst lawyer.
On the other side of the adversarial system are the policemen and the prosecutors. If Darwin was correct, then those best adapted will assume these roles – but best adapted to do what? If we want to achieve accurate justice, and avoid sending innocent people to prison, that is one thing; if we want to convict as many people as possible, that is another. The US prosecutorial system is focused almost exclusively on the latter goal.

I was talking to a couple of police officers not long ago and I asked them how many times, in their cumulative 54 years on the force, with thousands of arrests between them, they thought they might possibly, maybe have taken an innocent person into custody. Never! came the emphatic reply. Those people later found not guilty at trial? Guilty, all of them, or we wouldn’t have arrested them in the first place. So, we choose as police officers those whose predisposition leaves them most likely to make mistakes.

In the US, where district attorneys are elected, it is unlikely that the prosecutor will take a more sympathetic approach to the rights of the suspected criminal. Indeed, half of the prosecutors in one poll do not agree with the presumption of innocence; their office has already made the decision that the defendant is guilty when they send his case forward for trial.

Perhaps that is unsurprising: it would be difficult to drive to work pondering how many innocent people one was going to send to prison each day. There are exceptions to every rule, of course, yet generalisations are generally true. But surely, one hopes, these problems will be balanced out in the courtroom, where cooler judicial heads hold sway? Yet it is here that the system lets people like Kris down most abruptly.

In 1989, in Murray v Giarratano, the US Sup­reme Court came to one extraordinary conclusion – the US constitution does not require that a person who has been sentenced to death should be provided with a lawyer or any government funding to investigate his case and navigate the hypertechnical world of death pen­alty law once he has been convicted. For this reason, Kris has had to depend for his habeas appeals on me and a fellow volunteer, Ben Kuehne from Miami, since 1994.

Ben and I lost his appeals, in part because we had no money to bring all his witnesses to court to prove his case in post-conviction hearings. We cannot shoulder all the blame, however. If the Giarratano case was absurd, the rule of Herrera v Collins (1993) is fatuous: nothing in the US constitution, the Supreme Court tells us, says that an innocent person cannot be held in prison for the rest of his life, or even executed.

As the federal judge ruled in Kris’s case, “claims of actual innocence based on newly discovered evidence have never been held to state a ground for federal habeas corpus relief”. In plain English: whether Kris is innocent is not relevant to whether he should die in prison.

To be sure, we did ultimately get Kris a new sentencing trial because we proved that the prosecutor secretly wrote the order sentencing him to death. At that trial, because Kris stood convicted, Ben and I were told we would be held in contempt of court and sent to jail if we tried to suggest to the jury that Kris was not guilty. As fortune would have it, we prevailed regardless and he was resentenced to life – meaning that the earliest he can be considered for discretionary parole will be in 2040, when he is 101 years old. So he will still die in prison.

To an innocent man who is 73 years old, whose septuagenarian wife has stood by him for 26 years, it matters little, ultimately, whether he dies in the execution chamber or in a prison cell. How could the courts ignore the patent evidence of his innocence? It became very clear to me that the justice system is primarily interested not in justice, but in ensuring that nobody points to how the emperor is wearing no clothes.

The US has a terrible crime problem, one that presents American politicians with a challenge demanding expensive and complex solutions. They could crack down on guns, but that would offend the National Rifle Association. They could try introducing a national health service, but that would violate the constitutional right to suffer without treatment. They could experiment with a sensible welfare system, but that would be socialism. They might legalise many drugs, but common sense is not, as they say, so common.

The politician would rather turn to the tough-on-crime placebo. He pretends that the death penalty will solve America’s social ills, returning us to a golden age when all American children were above average and the policeman’s greatest challenge was a pedestrian crossing
the road before the little red man turned green. Thus, the politician assures us that the thin blue line of law enforcement is protecting us from the crime wave (rather than being part of a tidal wave of corruption). And the courts refuse to admit that the system often gets it horribly wrong, because if the emperor were seen to be naked, we might lose faith in the folly of our elected officials who sold us the system in the first place.

When I last saw Kris, he was shackled to a hospital bed, struggling to survive flesh-eating bacteria in his leg. He begged me to remember him and his faithful wife, Marita, every day. I want to make sure that he is never forgotten. More importantly, I want to make sure that the people who know what happened to Derrick and Duane Moo Young in that Miami hotel room that day in 1986 realise that Kris Maharaj is still behind bars and will die there if they don’t come forward.

We have proven that Kris is innocent to the satisfaction of any sane legal system, but that has not been enough. Someone out there has
a piece of information that will unlock his cell door – whether through looking at old records, or from casual words dropped by a close friend. If someone will just get in touch and tell us what they know, or even hint at where the answer can be found, we can still get this case back into court and locate justice for Kris. And if nobody does, an innocent man will die in prison, not as an anomaly, not just because I failed, but because the system made it turn out that way.

Clive Stafford Smith is the director of Reprieve (reprieve.org.uk). His book about the Maharaj case, “Injustice: Life and Death in the Courtrooms of America”, is newly publishedby Harvill Secker (£18.99)