The paper quoted unnamed "sources close to the investigation" as saying that evidence against Mr Castro was "already greater than the evidence that led to the drug indictment of former Panamanian strong man Manuel Noriega in 1988". The US invaded Panama the following year and snatched Noriega, who is now serving a 40-year sentence in America.
The drugs are said to have arrived in Havana aboard a Colombian freighter which off-loaded a cargo of soap, toothpaste, shampoo and toilet paper - scarce because of the US embargo. Protected by a Cuban gunboat, the drugs were shifted to power boats which then sped to the Florida Keys 90 miles away.
A Cuban embassy spokesman in Washington described the Herald report as "an outrageous lie". Pro-Castro Cubans said that the front page story was aimed at "staining" the Cuban leader on the eve of Cuba's biggest national holiday, on which Mr Castro usually gives his state-of-the-nation address. It marks July, 1953, on which Mr Castro initially launched his rebellion with an attack on a Havana military barracks, six years before his revolution finally triumphed.
The Herald story went on to quote "other sources" as saying: "Investigators have not been able to obtain a 'smoking gun' that establishes Castro's involvement", adding that he was unlikely to be named in an indictment.
Mr Castro's brother Raul, head of the Caribbean island's armed forces, has been named in previous US narcotics indictments. At Noriega's trial, former Colombian drug baron Carlos Lehder, himself serving a long term in the US, testified that Raul Castro had given him permission to smuggle cocaine to the US via Cuba.
Both Castro brothers have dismissed such reports as anti-Cuban propaganda. Four senior Cuban army officers and intelligence officials were executed after a show trial in 1989 for alleged drug trafficking.
The Miami Herald often leans towards Florida's large community of vehemently anti-Castro Cubans who fled the 1959 revolution, many of them influential in Florida and federal politics.
The drug arrest took place in Miami in January when police, following a tip about smuggled Cuban Cohiba cigars, raided a warehouse and found nearly three tons of cocaine. One Colombian and several Cuban Americans were detained, including 40-year-old Jorge Luis Cabrera, nicknamed "el Gordito" (the fat man), whose family owns a lobster and crab business in the Florida Keys.
The main basis for the supposed Castro link was alleged to be photographs found in a suspect's car at the scene of the bust, said to show "the fat man" posing with Mr Castro.
Mr Cabrera's lawyer said his client had visited Havana as a freelance photographer/ reporter for a Spanish-language Florida weekly. It seemed highly improbable that the shrewd Mr Castro would pose with a man with whom he was arranging a drug deal, or that the man or his alleged accomplices would carry such photographs in their car.
The Herald may have hit the nail on the head when, later in its story, it said that some of the alleged traffickers had begun co-operating with prosecutors in the spring, several months after the arrest.
"The incentive was great," the article said. "Implicating Castro could give the defendants great leverage in getting their sentences reduced or avoiding prosecution altogether."Reuse content