CBI on Thursday said it was probing the origin of a 'false, fabricated and forged' report, which had claimed that SP leader Mulayam Singh Yadav has been 'framed' in a disproportionate assets case.

CBI Director Ashwani Kumar said the agency would investigate the origin of the 'report', which was claimed to be an internal report of the agency, and as to how it reached the media. It would file its views before the Supreme Court once the agency's investigation is over, he said.