"You must destroy everything, everything, everything," Cilins allegedly instructed the wife of a deceased president of Guinea now living in Jacksonville, Fla.
The secretly recorded conversation is recounted in filings in federal court in Manhattan that detailed for the first time how, in the midst of an ongoing grand jury investigation, the FBI began tracking Cilins and his role as a globe-trotting emissary for wealthy Israeli mining magnate Beny Steinmetz.
Cilins, who was arrested in Jacksonville in April, has pleaded not guilty to U.S. charges that he was dispatched to Florida to convince the president's widow to destroy paperwork in her possession that, if made public, would expose how Beny Steinmetz Global Resources bribed officials in the impoverished West African nation to gain iron ore rights that the company turned into a multibillion-dollar windfall.
The Guernsey-based BSGR billed on its website as a "diversified natural resource business" that employs 6,000 people on four continents has vehemently denied any wrongdoing. The company "has never paid any money as bribes or blackmail," it said in a statement from its London office.
It added: "We have no reason to believe that Mr Steinmetz is under investigation in the US or elsewhere. Mr Steinmetz is a hugely respected businessman who has operated in dozens of countries for 35 years and has faced no evidenced allegations anywhere."
An FBI spokesman in New York declined to comment.
The controversy over the mining rights began in 2010, when current Guinea President Alpha Conde took office and began trying to undo a deal made by a previous administration with a reputation for corruption. BSGR has pushed back, claiming the project was legitimate.
A recent New Yorker magazine article described a 2011 meeting between Conde and Steinmetz in which Steinmetz asked, "Why are you against us?" Conde responded, "I have no personal problem with you. But I have to defend the interests of Guinea."
Caught in the middle is Cilins, described in defense documents as an honest family man from Antibes who spends "a significant amount of time" at a Miami synagogue when in the United States.
Cilins, 50, "is a successful businessman, buying and selling goods and service, as well as acting as a middleman in commercial transactions in Europe, Africa and South America," the papers say.
BSGR has said that "lacking a permanent presence in Guinea," it brought in Cilins because of his "extensive business operations" there.
Cilins claims that after the mining rights were secured, BSGR became the victim of a plot by Mamadie Toure identified by U.S. authorities as the fourth wife of the deceased Guinea president to use forged contracts to extort the company.
His phone calls and meetings with Toure were meant "to obtain these false documents so that he and BSGR and others could no longer be blackmailed or extorted," according to the defense. His lawyers have also questioned whether Toure was ever married to the president and suggested the U.S. investigation was prompted by a meeting between Conde and President Barack Obama, calling the case "politically motivated."
Prosecutors paint a much different picture. Toure's story, they insist, is credible. Attempts by The Associated Press to contact Toure were unsuccessful.
Toure, who began working with the FBI in March in hopes of gaining immunity in the U.S. case, had told investigators that while her husband was in power, Cilins and others secretly promised millions of dollars to her and government officials if they helped BSGR win over the president, prosecutors say in court papers that identify her only as a cooperating witness.
Prosecutors say the widow had proof: contracts in French and titled "Portocole D'Accord" and "Lettre D'Engagement" between her and BSGR that promised her $2 million in advance and $5 million more if the mining rights were granted. After agreeing to cooperate in the probe, Toure purposely tried to spook Cilins by telling him the FBI was closing in and wanted her to turn over the contracts to the grand jury.
"We need to urgently, urgently, urgently destroy all of this," he allegedly responded in one of many conversations monitored by the FBI.
Cilins assured Toure that he had the blessing and funding from someone prosecutors label a co-conspirator but only identify as a "high-ranking individual" at BSGR.
"What I was asked to do is to watch when the documents are destroyed ... to be 100 percent sure that everything is destroyed and that nothing is dispersed," Cilins said in a whisper, according to prosecutors.
Cilins offered to give Toure $1 million once he witnessed the burning of the contracts, the papers say. But he also insisted she sign a sworn statement saying she never received money from BSGR and never intervened on its behalf in the Guinea mining deal.
FBI agents arrested Cilins at a Jacksonville airport after he and Toures met one last time. Agents discovered he was carrying more than $20,000 in cash.