The clamour by the UPA Government to probe spectrum allocation during the NDA regime seemed to grow weak on Thursday with the Central Bureau of Investigation (CBI) finding little or no evidence of irregularity against Pramod Mahajan and Arun Shourie. Submitting the status report of CBI before a bench of Justices GS Singhvi and AK Ganguly, senior advocate KK Venugopal said that the investigation into alleged irregularities during the tenure of Mahajan and Shourie has yielded little, although investigations in this regard is expected to complete by September 30.