Blinded by the sun, John Favara ran over and killed the 12-year-old son of his neighbour in New York when the boy rode his mini-motorbike into the street on March 18, 1980.

To his great misfortune, the neighbour was John Gotti, who was soon to become the Godfather of the American Mafia. Four months later Mr Favara vanished.

The 51-year-old furniture salesman and father of two, who had no links to the Mob, received death threats before his disappearance. His wife and two children fled their home in an Italian-American neighbourhood but were tormented by a campaign of letters containing excrement.

His body was never found, and prosecutors now believe that they know why. Almost 30 years later, an informant cited in court papers in an impending Mafia trial says that Mr Favara was murdered and disposed of in a barrel of acid. Charles Carneglia, the defendant, allegedly told the informant that acid was “the best method to use to avoid detection”.

Mr Favara lived one street away from Mr Gotti and his five children in the New York neighbourhood of Howard Beach. His son Scott was a friend of another of Gotti’s sons, John Jr, who, prosecutors say, grew up to succeed his father as head of the Gambino crime family.

The salesman’s car hit Frank, the Gottis’ youngest child, when he darted in front of him. Police accepted that the child’s death was an accident. But John Gotti, a fast-rising gangster who took over the Gambino family with the spectacular murder of its boss, Paul “Big Paul” Castellano, in 1985, was not content to let the matter rest.

Two days after the accident, a woman called the local police station and said: “The driver of the car that killed Frank Gotti will be eliminated.”

Mr Favara began receiving death threats — including an invitation to his own funeral. His car was stolen and found spray-painted with the word “Murderer”. At first he dismissed the danger, saying: “That kind of stuff only happens in the movies.”

He tried to apologise to Victoria Gotti, the dead boy’s mother, but she chased him away with an aluminium baseball bat.

After that he decided to move and signed a contract to buy a new house. While waiting for completion, however, he was snatched by a group of men as he left the Castro Convertible furniture warehouse in Long Island on July 28, 1980.

Four witnesses at a nearby diner saw a group of men beating him with a plank of wood, before shooting him in the legs and driving him away. The terrified witnesses refused to co-operate. The owner of the diner sold up and moved away after one of the suspected hitmen came in and stared at him menacingly over the counter.

Gotti, who was eventually convicted for his Mob activities and died in jail in 2002, was the obvious suspect, but the Gottis had hotel receipts showing that they were in Florida on the day that Mr Favara disappeared.

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