Ms Lagarde has yet to be placed under formal investigation in the case and has denied any wrongdoing.

BBC: IMF 'has confidence' in Christine Lagarde

There is speculation in France that Ms Lagarde could yet be placed under formal investigation in this case, he adds.

BBC: French court summons IMF chief over Bernard Tapie probe

She could be placed under formal investigation for the decision to use arbitration, against advice from senior advisers, to settle a long-running court battle between the state and Mr Tapie, a supporter of the then French President, Nicolas Sarkozy.

BBC: French court questions IMF chief Christine Lagarde

Business managers can also be placed in jail while they are under investigation, say people familiar with Kazakh law.

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However, our correspondent says that Ms Lagarde's position at the IMF could be in jeopardy if she is placed under formal investigation.

BBC: IMF head Lagarde's flat searched in Bernard Tapie probe

"It is under investigation and charges may be placed, " Mr. Nunley said.

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