Prosecutors in Switzerland have formally indicted former SNC-Lavalin executive Riadh Ben Aissa on allegations he laundered vast sums of money tied to at least $139 million in mysterious payments by the company, according to Swiss public broadcaster RTS.

CBC News has also learned RCMP officials are working with Swiss police and have travelled to Switzerland to assist in the joint investigation.

Citing multiple confidential sources in Switzerland and North Africa, RTS investigative reporter Yves Steiner told CBC News that Swiss authorities have tracked money flowing from the Canadian engineering conglomerate to Swiss bank accounts registered to companies in the British Virgin Islands. Some of the funds then went directly into Swiss bank accounts controlled by Ben Aïssa, Steiner said his sources told him, and Swiss officials are working with the RCMP to get to the bottom of the mystery.

"Swiss investigators are interested in this network of companies and accounts, transfers that were allegedly authorized by Riadh Ben Aissa to obtain contracts in Tunisia and, especially, Libya," RTS reported Sunday.

The RCMP has not commented on these latest reports but has previously refused to answer questions, citing the ongoing investigation.

Ben Aissa was arrested in Switzerland last spring and remains in jail on suspicion of money laundering and corruption of public officials related to his business dealings in North Africa.

Prosecutors have also charged Geneva-based lawyer Roland Kaufmann with money laundering and corruption. According to RTS, authorities accuse him of helping Ben Aissa to set up two companies, Dinova and Duvel Securities, registered in the British Virgin Islands. The broadcaster reports investigators are probing millions of dollars in payments from SNC-Lavalin to those companies’ Swiss bank accounts dating back as early as 2001.

CBC News placed multiple calls to the lone directors listed on the company registration records in the BVI for Dinova and Duvel Securities, but neither director returned calls.

Swiss authorities are still trying to sort out the exact movements of the $139 million, Steiner said, and have interviewed several SNC-Lavalin officials. CBC News has confirmed that some interviews were completed in April, and that Sami Bebawi, Ben Aïssa's predecessor as head of international construction projects, flew to Switzerland last week to talk to Swiss prosecutors.

"I have many, many sources who say, 'OK, there is a system of corruption, there is a system of money laundering — or could be used for this kind of thing at least — in fact based here in Geneva,'" Steiner told CBC News.

$139M more than double what SNC audit found

The RTS report that investigators are tracking $130 million Swiss francs ($139 million Cdn) only deepens the mystery around SNC-Lavalin payments to procure construction projects given the company’s own announcement in March that audits had discovered only $56 million in improper payments.

Neither Ben Aïssa's Canadian nor his Swiss lawyer would comment on these latest allegations. Reached Saturday, Canadian lawyer Michael Edelson did say, however, that Ben Aissa is not pleased with a recently launched civil suit by his brother against SNC. On Nov. 5, orthopedic trauma specialist Rafik Benaissa filed a $5-million lawsuit against SNC-Lavalin accusing the company of using his brother as a scapegoat and damaging his family’s name.

"SNC-Lavalin knowingly allowed and condoned the use of millions of dollars to fund lobbyists in the Middle East to get lucrative contracts with major leaders of some countries, particularly in Libya," the suit claims. None of its allegations have been tested in court.

The company declined CBC’s request for an interview with its CEO and would not answer whether Riadh Ben Aissa could have singlehandedly approved and concealed the $139 million in payments.

“We continue to collaborate in all investigations with authorities as they are pursued,” SNC-Lavalin spokesperson Leslie Quinton said in an emailed statement.

“Because these investigations are ongoing and we continue to cooperate, unfortunately there is nothing further that we are able to add at this time, except to reiterate that we hope that if anyone is found to have committed any wrongdoing, they are brought to justice,” she said.

The ultimate purpose of the $139 million in SNC-Lavalin payments remains unclear.

However, an SNC insider — the same person who anonymously accused Ben Aissa of wrongdoing in a December 2011 "poison pen" letter to company directors and executives — told CBC News "more has to be done" within the company.

"There is no way that kind of money is moved without approvals" from people still within the company, the source said. "Employees who detested the rule of Ben Aissa are sympathetic to Ben Aïssa's [brother's] lawsuit that claims that the management knew and encouraged his acts.

"This is not a story of foreign criminals, but a sad story of Canadian greed."