(CNN)On an August afternoon in 1991, a federal judge in California sent an unmistakable message in the "war on drugs" when he sentenced four men convicted of laundering cocaine cartel cash to more than 500 years each in prison.
These men received 505-year prison sentences each. Now their cases are under new scrutiny
None of the men had previous criminal records. Nor were they convicted of direct involvement in the massive cocaine distribution ring at the center of the case.
The sentences by US District Court Judge William D. Keller were considered harsh even back then and represent the sort of draconian punishment that has since been widely condemned amid a national conversation around justice reform.
For decades, the men sentenced by Keller that afternoon seemed destined to die in prison, just as the judge predicted they would.
Then last year, they got what appeared to be an extraordinary reprieve:
Federal prosecutors, who had been investigating defense claims of undisclosed special treatment given to a key government witness by FBI agents, recommended that the men's convictions be overturned "in the interests of justice" and that they be released from prison right away.
All that stood between the four men and their freedom was the blessing of another federal judge. That seemed likely given that prosecutors had taken the highly unusual step of siding with the defense in seeking to have the convictions thrown out.
But US District Court Judge Stephen V. Wilson, a former prosecutor himself who once worked under Keller in the US Attorney's Office in Los Angeles, was not inclined to simply "rubber stamp" the request.
Wilson had questions, and his search for answers was going to take time.
In the eyes of prosecutors in the early 1990s, brothers Nazareth and Vahe Andonian, Raul Vivas, and Juan Carlos Seresi may not have personally committed any acts of violence or handled any kilos of cocaine, but their activities enabled those who did. The more than $300 million the men helped launder, the logic went, kept the cartels in business.
Even before trial, Judge Keller, who was appointed to the federal bench by President Ronald Reagan in 1984, made his disdain for such crimes known.
"I intend to deter forevermore anybody doing anything like this," he said at a pretrial hearing.
At trial, defense attorneys depicted their clients as legitimate businessmen whose participation in any sort of money laundering scheme was unwitting. They acknowledged the men had been involved in massive financial transactions through their precious metal and money exchange companies, but denied they had any knowledge that their activities involved money derived from illicit sources. The Andonian brothers and Vivas were already successful business owners before the alleged crimes began, according to court records. Seresi worked for Vivas.
The trial lasted eight months, and the jury was out for another 28 days. The panel could not reach a verdict on drug conspiracy charges against the men, resulting in a hung jury on those charges. But they were each convicted of multiple counts of money laundering and conspiracy.
At sentencing, Keller made good on his earlier comment about deterrence. He detailed how he put together a string of consecutive terms intended to put the men away not just for one lifetime, but many.
The judge alluded to the apparent finality of the sentences when he temporarily balked at ordering any sort of customary post-release supervision.
"It just flies in the face of common sense," Keller said. "I don't anticipate there is going to be any release."
On top of the prison terms, Vivas was fined $7.6 million and the Andonians $1.7 million each. Seresi, in a nod to what Keller acknowledged was his "rather modest means," was spared a fine.
For two decades, the Andonian brothers, Vivas and Seresi, tried to make the most of life behind bars. They stayed connected with their expanding families, memorized grandkids' birthdays, earned college degrees, worked with their attorneys filing appeals.
Their legal efforts, however, always ended in disappointment.
But in 2012, a man who played a key role in putting them in prison would set in motion their best chance of getting out.
That man is Sergio Hochman, a co-conspirator who once worked at a Los Angeles gold brokerage used in the money laundering scheme, according to court filings.
Hochman, who was facing a potential life sentence in a related case, cut an early deal with prosecutors. He spent seven days on the witness stand testifying for the government. He described how "bulk cash" from narcotics sales were used to buy gold. The gold was then sold, and the proceeds were wired to Central and South America.
Hochman explained a code used to discuss financial transactions at issue in the case and his testimony helped bolster the prosecution's contention that the defendants knew the money was dirty.
What jurors didn't know was that Hochman had been receiving special treatment from his FBI handlers, including a handcuff-free seaside lunch in Malibu and visits with his wife in the backseat of a car and in her apartment in Tucson, Arizona.
In exchange for his cooperation, Hochman received a sentence of five years and eight months and was released in 1994. In fact, all of the defendants convicted along with Hochman in his case and sentenced by Judge Consuelo B. Marshall have since been released from prison.
Hochman first disclosed some "benefits that he received" to his own attorney in a conversation 18 years after his release, according to a declaration by the lawyer, Errol Stambler.
Stambler said he realized what Hochman was alluding to was new information and pressed him for more detail. He said Hochman was initially "very reluctant to share more," but a few months later signed a sworn declaration detailing the special treatment. In it, he said he had been warned by his FBI agent handlers "not to disclose those benefits to anyone."
As a result of the warning, Hochman wrote, "I remained silent and did not volunteer that information to anyone, not even to my attorney."
For prosecutors -- and by extension their investigators -- failing to turn over evidence that might point toward a defendant's innocence or raise serious questions about his guilt is considered a cardinal sin and can lead to convictions being overturned. Special treatment given to a key witness by FBI agents and withheld from defense attorneys could fall into that category.
Recognizing the potential importance of Hochman's declaration to the imprisoned defendants, Stambler turned the document over to Vivas's attorney, Alan Eisner.