* Prosecutors to question former Gunvor agent
* Case could shed light on secret trading world
* Gunvor filed criminal complaint for embezzlement
* Case may signal Swiss serious about improving image
By Emma Farge
GENEVA, Feb 12 Switzerland has stepped up a criminal investigation into an oil contract in the Republic of Congo and will question a former Gunvor employee and his associate on suspicions of fraud, the company confirmed.
The attorney general originally opened the money laundering investigation in late 2011 but did not have sufficient evidence until last month to identify the individuals and proceed with questioning.
At issue is whether the former Gunvor agent and his associate siphoned off millions of dollars in connection with a contract in the former French colony in West Africa, worth over $2 billion according to Swiss newspaper Le Temps.
In accordance with Swiss privacy laws, the individuals were not named, although the same paper referred to him as a 40-year-old Belgian. Gunvor itself is not the subject of the investigation.
"We've found real links which we think justify to open an investigation against specific people. We are now proceeding with legal mutual assistance requests and analysing the financial flows," Swiss Attorney General Michael Lauber said in an interview.
"One of the goals to find out is if these people belong to a system or if they acted on their own," he added.
The attorney general's office confirmed that the suspicions were fraud, criminal mismanagement and misappropriation and that the latest stage of the preliminary proceedings had begun on Jan. 17.
Swiss-based Gunvor confirmed that in November it filed a criminal complaint with the attorney general alleging fraud and embezzlement against the former employee, whom it dismissed last year. Gunvor is now a plaintiff in those proceedings.
It declined further comment.
Lauber described the case as "complicated" and said it was likely to involve requests for judicial assistance from several countries, declining to name them.
If the case goes to court, it could shed light on the normally secretive world of oil trading, in which firms jockey for lucrative contracts with African governments.
Gunvor, which trades around 2.5 million barrels of oil each day, stepped up activities in the west African region in 2009-2010 when it hired a team of experienced traders from Geneva-based rival Addax Petroleum, industry sources said.
Previously the dominant buyer of Russian oil, Gunvor has sought to diversify its sources of crude in recent years and now buys from more than 35 countries.
Gunvor, co-owned by Gennady Timchenko and Torbjorn Tornqvist, is also one of a handful of Swiss trading houses with an oil export contract from Nigeria.
The case would signal to critics that Switzerland - a major hub for oil trading and banking - is serious about improving its image as a transit point for suspicious money flows.
Lauber said 200 to 400 money laundering cases were reported to the attorney general each year.
Switzerland identified a record amount of suspicious money flows at more than 3 billion Swiss francs ($3.26 billion) in 2011. ($1 = 0.9195 Swiss francs) (Reporting by Emma Farge; Editing by Stephanie Nebehay and Jane Baird)