Colombian authorities plan to question Swiss hostage mediator Jean-Pierre Gontard amid allegations he transported ransom money to leftwing rebels.
Gontard and the Swiss foreign ministry have rejected the claim, which dates back to the 2001 release of two employees of Swiss pharmaceutical giant Novartis who had been kidnapped by the Revolutionary Armed Forces of Colombia (Farc).
The Colombian government has accused Gontard of carrying $500,000 (SFr503,000) for the Farc.
The Colombian public prosecutor told a news conference in Bogotà it was appropriate to launch a formal investigation into the matter, including a hearing with Gontard.
However, no date has been set for the meeting. Reports say a representative of an independent organisation might take part in the hearing, possibly in Switzerland.
Together with France and Spain, Switzerland had tried to secure the release of hostages in Colombia for several years.
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