The Supreme Court on Thursday came down heavily on the CBI for failing to question former Telecom Minster A. Raja and Telecom Secretary in the 2G Spectrum scandal. A bench of justices G S Singhvi and A K Ganguly wondered why the premier investigating agency failed to question the duo despite the CVC and CAG report sharply indicting them for their involvement.Explaining the delay, senior counsel K K Venugopal submitted that the CBI has got its own methods of investigations.