Image source, Getty ImagesImage caption, Jimmy Hoffa's disappeared in 1975 after his friendship with a mafia boss soured

FBI agents have searched a plot of land in the US state of New Jersey after a deathbed confession renewed hope of solving union boss Jimmy Hoffa's disappearance 50 years ago.

For decades, Hoffa was one of America's most powerful labour organisers.

But in 1975 he suddenly disappeared and his body has never been recovered.

Investigators recently received a tip that a former worker on a landfill site in Jersey City had said that his father told him he had buried Hoffa's body.

His disappearance had long been linked with the American Mafia, with whom Hoffa had a turbulent relationship.

According to the New York Times, landfill worker Frank Cappola, who died in March 2020, told a friend that his father had confessed to him that he had been ordered by a gang of unidentified men to bury Hoffa's body underground in a steel drum.

Agents bearing search warrants arrived at a former landfill site and conducted a survey on 25 and 26 October. A spokesperson for the FBI told the newspaper that data was currently being analysed.

Hoffa was born in the tiny city of Brazil, Indiana in February 1913, and by 1957 had become one of the most powerful union leaders in the country after taking charge of the International Brotherhood of Teamsters.

Throughout his time in charge of the union, Hoffa was frequently accused of association with the American mafia and organised crime.

Robert Kennedy, as attorney general under his brother President John F. Kennedy, tried to convict him for a variety of offences during his time in office and formed a "Get Hoffa" unit of prosecutors to take action against his activities.

Kennedy's efforts finally paid off when Hoffa was convicted of jury tampering in 1967, but he was later released by President Nixon in 1971 as part of a deal that forced him to step down from the teamsters leadership.

By summer 1975, Hoffa had lost his once considerable power and his friendship with the New Jersey Mafia boss Anthony Provenzano, nicknamed "Tony Pro", had soured badly.

He disappeared on 30 July 1975 after travelling to Michigan to meet the mobster. Ever since his story, told in the 2019 film the Irishman, has fascinated investigators.

There have been several failed searches for Hoffa's body over the years. In Michigan, where Hoffa was last seen, investigators have searched many sites, from a farm to beneath a swimming pool.

And in New Jersey, an urban legend has long claimed that Hoffa's remains were buried under the old New York Giants football stadium.