The investigation agency had wanted to know if its failure to challenge Dutt's acquittal from terror charges might strengthen the appeals of other terror convicts in the Mumbai serial bombings case.

Dutt, now a Samajwadi Party general secretary, had moved the apex court challenging his conviction for possessing illegal arms. The case relates to the Mumbai bombings that followed the 1992 razing of the Babri mosque in Uttar Pradesh.

Dutt was sentenced to six years of jail July 31, 2007 by the Mumbai anti-terror court of special judge P.D. Kode. He was given bail by the apex court Nov 27, 2007 after the CBI took a lenient view against him and other similarly placed people convicted of charges other than terrorism.

The 1993 terror bombings, which claimed 257 lives, have been blamed on the Mumbai underworld and Pakistani intelligence agencies. Its targets included Mumbai landmarks such as the Bombay Stock Exchange and Air India headquarters.