Krishna Maharaj, once Britain's second biggest racehorse owner and regularly in the company of royalty, has languished on death row in Florida for the past 15 years. His health has declined as he protests his innocence.

Amid this gloomy predicament, however,is a slight chink of light. A US court will hold a re-sentencing hearing tomorrow – the start of a long legal process which may eventually see Maharaj retried and, say his supporters – a number of MPs among them – found innocent.

"Of the 300 or more death row cases I have dealt with, this is by far the most clear-cut case of someone who is innocent," said his lawyer, Clive Stafford Smith. "Not only can we prove that Kris did not do it, but we can show who did."

Unlike Tracy Housel, the Bermudan-born British citizen executed in Georgia last week, Maharaj has close links with the UK. He was born in Trinidad in 1939 and moved to Britain in 1960.

Starting as a van driver, he built up a multi-million pound business importing bananas, ran a string of racehorses and owned 24 Rolls-Royces.

In the mid-'80s, he and his wife, Marita, moved to America, where he set up a property investment company. But he believed he was swindled out of $600,000 by an associate, Derrick Moo Young. For months the pair were involved in a bitter and very public feud.

On 16 October 1986, Maharaj was due to meet Moo Young and his son Duane in a penthouse suite of the Dupont Plaza Hotel in Miami. It was there that police later found the father and son lying in a pool of blood. Both had been shot dead, and suspicion instantly fell on Maharaj.

At his trial, Maharaj's lawyer failed to call witnesses who would have testified that he was 25 miles away in Fort Lauderdale at the time. Even more astonishingly, halfway through, the judge, Howard Goss, was led away in handcuffs after being accused of taking a bribe over the case. Maharaj's appeal team later argued that a go-between for Goss asked their client for $50,000 to fix the trial.

Maharaj meanwhile requires 10 different medicines every day for a variety of conditions, including diabetes. "It's like living a nightmare", says his wife.