An FIR was lodged against SP general secretary Amar Singh and his wife Pankaja Kumari Singh in Kanpur on Thursday for alleged financial fraud amounting to about Rs 500 crore, a senior police official said Lucknow.

The case was lodged at Babupurwa police station, charging the leader with amalgamating companies for converting black money into white, Additional Director General of Police (Law and Order) Brij Lal said.

Shiv Kant Tiwari, in his 14-page complaint, alleged that between 2003-2008 the couple amalgamated their companies with other holdings and had amassed nearly Rs 500 crore in the process, DIG (Kanpur) Neera Rawat said.

The companies named in the FIR included Energy Development Company Limited, EDCL Power Limited, Pankaja Art and Credit Limited, Sarvottam Cap Limited, EDCL Infrastructure Limited and Eastern India Company, all owned or run by the Singh couple.

"The complainant alleged that small utilities were amalgamated in these companies. For instance, he claimed that 25 companies were amalgamated in Sarvottam Cap Limited," the ADG said.

He said that name of actor Amitabh Bachchan had also been mentioned in the complaint.

"The FIR has been lodged under various sections of IPC, Prevention of Corruption Act and Prevention of Laundering Act," he said.