A British businessman who has been in a Florida prison cell for the past 28 years – 15 of them on death row – will have a last chance to prove his innocence at an evidentiary hearing into his double murder conviction that opens in a Miami court on Monday.

Krishna, known as Kris, Maharaj will appear on Monday morning before Florida’s 11th circuit court, in a last-ditch attempt to prove that he has been the victim of a gross miscarriage of justice. His lawyers expect to call up to eight witnesses and present the court with 50 documents that will in their submission conclusively show that he was framed for the murders and that his prosecution was at best deeply flawed and at worst blatantly corrupt.

Among the first witnesses expected to give evidence will be a former Miami police officer who is expected to testify that he witnessed his senior officers planning a frame-up. In a recent affidavit the former officer, who is himself in prison on unrelated charges, said: “I visited the scene of the crime when it happened. I know that Mr Maharaj was framed because one of the officers in charge of investigating the double murder told me flat out that they were going to do this.”

Among the other witnesses will be three people previously connected with Colombian drug cartels, who will testify that the murders were linked to drug trafficking and that Maharaj was set up as a fall guy. A former agent of the federal Drug Enforcement Administration will also give evidence about a cartel conspiracy.

Clive Stafford Smith of the international human rights organization Reprieve, who has been representing Maharaj for 20 years, told the Guardian Monday’s hearing amounted to a “life-or-death situation. Kris is no longer on death row, thank goodness, but he is 75 years old, in bad health, and will die in prison if he’s there much longer. So this is his last chance.”

Even in Florida, a state that has seen its fair share of human highs and lows, the fall from grace of Trinidadian-born Maharaj was particularly spectacular. At one point he was a multimillionaire with a lucrative banana-importation business that supported lavish tastes in Rolls-Royces and racehorses.

By 1986 he was in financial difficulties, as a result of a real-estate scheme in which he said his business partner, a Jamaican called Derrick Moo Young, had defrauded him of $400,000. Maharaj was suing Young over the affair.

On 16 October 1986, Maharaj went to the Dupont Plaza hotel in Miami for a meeting, waiting in room 1215 for an associate who he said failed to show up. When Young and his son Duane were found later that day, shot dead in the hotel, Miami police latched on to Maharaj as prime suspect.

He was arrested that evening and put on trial the following year. He was initially sentenced to death, but in 2002 the conviction was commuted to a life sentence after it emerged that the original trial judge had committed misconduct.

Over the past two decades, Maharaj’s legal team has painstakingly pieced together a very different story of what happened that day. His lawyers discovered that senior members of the Pablo Escobar Colombian drug cartel were based at the time of the murders in an adjacent room on the 12th floor of the Dupont Plaza.

Derrick Moo Young had been embroiled with the cartel, laundering billions of dollars for them but falling out with them when they learned he had been taking a cut of the money for himself.

The evidence to be presented to court this week will seek to show that Maharaj was lured to the hotel to set him up for the cartel’s murder of Young and his son, which was then covered up by the Miami police. Stafford Smith said the city’s police force was riddled with corruption in the mid-1980s, fueled by the massive cocaine trade for which Miami was the main point of entry from Colombia into the US.

“There was so much money involved in narcotics work that corruption was endemic,” he said.

Florida state authorities continue to insist they got the right man. They will be presenting their own witnesses this week and will argue that the case that Maharaj is innocent is based entirely on inadmissible hearsay.

The judge presiding over the hearing, William Thomas, has indicated he wants to push ahead with a quick hearing followed by a prompt ruling, which Maharaj’s legal team hope may come by the end of the year. Thomas has the power to order a retrial, or potentially even exonerate and release Maharaj.

Stafford Smith said Maharaj was optimistic about the outcome, “But poor old Kris has been optimistic for the past 28 years.”

In an article in the Guardian earlier this year, Maharaj described his life in prison: “They spend an average of $1.67 (£1) a day on my food here, and you can imagine what one gets for 56 cents a meal.

“I used to have a German shepherd called Jason – how I loved that dog! – and he would bite me and run away if I fed him this stuff.”