Sinha had met the accused in the 2G and coal scam cases which were being investigated by the probe agency when he was heading it.
Reposing faith in the existing set-up of the CBI, a bench of Justice Madan B. Lokur, Justice Kurian Joseph and Justice AK Sikri, declined a plea by NGO Common Cause seeking probe by an outside agency.
Pronouncing the order, Justice Lokur said that since the new CBI director was not conversant with the legal aspects of the case, he would be assisted by senior counsel, who is also the Special Public Prosecutor in the 2G scam cases.
The court said that the CBI director would have the assistance of two officers of the agency in carrying out the probe against Sinha.
The court order came following a report by the CBI's former Special Director ML Sharma, who had examined all the papers, including visitors' entry register that was maintained at the official residence of Sinha when he was heading the agency.