German prosecutors investigating the funding scandal of former Chancellor Helmut Kohl's Christian Democratic party have asked the Swiss for information relating to the sale of an oil refinery in Eastern Germany.
Geneva's chief prosecutor, Bernard Bertossa, has been investigating the takeover of the Leuna refinery by France's Elf-Aquitaine.
Responding to an offer by Bertossa, the German justice ministry on Monday requested that he forward the files to state prosecutors in Karlsruhe. A parliamentary committee also wants to scrutinise the documents.
The Geneva prosecutor's office has been looking at Elf's 1992 purchase of the Leuna refinery to see whether any of the alleged bribes paid as a result of the deal were laundered through Switzerland.
Bertossa said the Leuna affair involved payments of about SFr1 billion ($560 million). Some of the money was apparently channelled through Switzerland and Liechtenstein.
In March, the German government filed a complaint in France over the Leuna sale, alleging that $37 million was paid to a middleman, some of which may have ended up in the coffers of the Christian Democrats.
The head of the parliamentary committee, the social democrat Volker Neumann, hopes the files will contain the names of those who received bribes. He believes this may force prosecutors to launch new investigations into the case.
The Christian Democrats have denied it received any cash from the deal. However, the party has admitted accepting DM2 million in secret donations in the 1980s, when it was in power.
Bertossa has been taking an interest in Elf for some time. Earlier this month, the prosecutor froze SFr800 million in Swiss banks thought to come from bribes channelled from Elf to help another French firm land a Taiwanese warship contract.
swissinfo with agencies