The Central Bureau of Investigation has sought the Union home ministry's nod before proceeding to find out from Switzerland [Images] the source of Rs 21 crore which were routed to Italian businessman and Bofors case accused Ottavio Quattrocchi's bank accounts in London [Images].

CBI sources said the agency had sent in the draft of the Letter Rogatory but there has been no response from the ministry so far. The Letter Rogatory, which would be sent to the Swiss authorities once the clearance is secured, would seek details of the fund transfer from Lugano in Switzerland.

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The CBI had earlier been informed that the money in the two bank accounts -- 5A5151516L and 5A5151516M -- with BSIAG Bank, London, having three million Euros and one million dollars respectively -- had come from the Bahamas. The agency had secured a Letter Rogatory in 2004 for Bahamas, which was executed in 2005.

During the probe in Bahamas, CBI sleuths found that the money had not been transferred from there. The sources said that during further investigation, the CBI found that the money had come from the Swiss city of Lugano and details would be sought from them.