The court, however, dropped the CBI probe against Dimple Yadav, wife of Akhilesh Yadav, saying that she was not holding any public office and she was only a private person holding no position.
The apex court said "CBI is an independent body" and it is free to proceed with the probe against Mulayam and his two sons--Akhilesh and Prateek--in accordance with the law.
A bench comprising Chief Justice Altamas Kabir and H L Dattu refused to alter the March 1, 2007 order for CBI inquiry against them saying that "the proceedings in the review petition cannot be converted into the appeals".
The bench also accepted that its direction in the March 1, 2007 order directing the CBI to place the report of progress into the investigation before the Union Government suffered from "error" and required modification.
The court said it is "not contemplated in the Delhi Police Establishment Act" under which CBI functions that the agency has to file its status report to the government and there was a need for modifying its earlier order.
"We are modifying our order of March 1, 2007 to remove the error in it directing CBI to place the report before the government," the bench said.
The bench said, "Since CBI is an independent body, there is no obligation for it to file the status report before the government".
"CBI, which is probing the case, has to decide what steps it has to take," it said.