WASHINGTON (CNN) - Felix Sater -- the Trump Organization contact who pushed for a Moscow development project and Mueller investigation witness -- was a decade ago a federal government informant to "a depth and breadth rarely seen" against Russian and American mobsters, fraudsters, cyber-criminals and even Osama bin Laden, according to newly unsealed court filings on Friday.
"For approximately 10 years, Sater continuously worked with prosecutors and law enforcement agents to provide information crucial to the conviction of over 20 different individuals, including those responsible for committing massive financial fraud, members of La Cosa Nostra organized crime families and international cyber-criminals," prosecutors wrote to a federal judge 10 years ago. "Additionally, Sater provided the United States intelligence community with highly sensitive information in an effort to help the government combat terrorists and rogue states."
Sater led federal investigators to information about missile and precious metals trafficking as well as New York City's Genovese and other crime families and those involved in so-called "Pump and Dump" and "Boiler Room" 1990s-era trading schemes.
He also gave US government officials what they "believed to be bin Laden's satellite telephone numbers and information about who was supplying arms to bin Laden," the prosecutors wrote at the time, about two years before the terrorist leader was killed in a US military raid.
The filings, from before Sater's sentencing in 2009, describe in detail the extensive help he had given federal investigators in intelligence and law enforcement matters. He pleaded guilty to racketeering in the case that established his cooperation in 1998, and was fined $25,000 as his sentence.
"His cooperation has covered a stunning array of subject matter, ranging from sophisticated local and international criminal activity to matters involving the world's most dangerous terrorists and rogue states," his attorneys wrote 10 years ago.
His cooperation ended after The New York Times printed an article in 2007 about his work as a developer in the Trump Soho project and a Trump tower and hotel in Florida and his efforts as an informant, his attorneys said.
The documents unsealed Friday -- a memo from prosecutors describing his cooperation and a letter from his attorneys to the judge before sentencing -- do not relate to his associations with Trump aside from a mention of the Times article.
Yet in recent years Sater has been aligned more closely with Trump Organization projects, including up until 2016. He spoke to the office of special counsel in 2017 as a witness.
Sater was an executive at Bayrock Group, which licensed the Trump name to build properties in New York and Florida. Donald Trump and Sater appeared at public events together, gave joint interviews and co-signed paperwork relating to their business deals. But in a 2013 deposition, Trump distanced himself and said he didn't know Sater well.
Sater's name, however, came up frequently in special counsel Robert Mueller's investigation into Russian interference in the 2016 US election.
In 2015, Sater had contacted Trump's personal lawyer Michael Cohen about the possibility of developing a Trump Tower in Moscow. Trump approved of the negotiation, and it continued into 2016 before evaporating, Mueller said.
"In early negotiations with the Trump Organization, Sater had alluded to the need for government approval and his attempts to set up meetings with Russian officials," Mueller wrote, citing an email between Sater and Cohen.
"Beginning in late 2015, Sater repeatedly tried to arrange for Cohen and candidate Trump, as representatives of the Trump Organization, to travel to Russia to meet with Russian government officials and possible financing partners," the Mueller report said. Sater continued to discuss the Moscow trip into the spring of 2016, but it never happened.
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