New Delhi, Aug 27 - Congress president Sonia Gandhi's desire to get to the truth has led to yet another extension for a panel probing the possible 'larger conspiracy' behind former prime minister Rajiv Gandhi's killing, official sources said Thursday.

The Multi-Disciplinary Monitoring Agency (MDMA), which was set up in 1998, won another one-year life last week.

According to sources in the Central Bureau of Investigation (CBI), this happened because of the 'keen interest' shown by Sonia Gandhi to get to the bottom of the May 1991 assassination.

A CBI source, however, admitted to IANS that the probe panel has failed to make any major breakthrough in the last 11 years in exposing any 'larger conspiracy' behind the killing of Rajiv Gandhi at an election rally near Chennai.

The Liberation Tigers of Tamil Eelam (LTTE) was blamed for the grotesque killing.