Mumbai, Mar 19 (IANS): The admission to guilt by Pakistani American terror suspect David Headley to terror charges against him is "a major victory for Indian investigators" and proves that Pakistani terror accused Mohammed Ajmal Amir alias Kasab was "speaking the truth", the prosecutor heading the 26/11 Mumbai terror attacks trial said.

"Headley's confession and his admission to all the 12 charges against him has substantiated our claim that the Lashkar-e-Taiba (LeT) was directly behind the terror attacks," special public prosecutor Ujjwal Nikam told IANS here Friday.

Kasab had mentioned certain aspects about Headley's involvement in the Nov 26, 2008 terror attacks and the developments in Chicago prove that "he was speaking the truth", Nikam said.

It is also clear that there are certain state sponsors of the terror attacks in Pakistan and the entire conspiracy of the attack was hatched in that country, he said.

Among other things, Headley has confessed to working on behalf of several terror groups, including the LeT, before a Chicago court.

Nikam said that the LeT used different terror modules and sleeper cells to collect information about Mumbai, and Headley belonged to one such module.

Members of another module - Fahim Ansari and Sabahuddin Ahmed - have also been nabbed and are currently undergoing trial in Mumbai as co-accused with Kasab.

"Now, I hope that the US government will part with the evidence and information against Headley to enable Indian authorities to track down the network and other modules of the LeT in India and elsewhere," Nikam urged.

"As far as the 26/11 trial is concerned, the Headley developments shall have no impact and we shall continue as usual," said Nikam, who is soon to complete the critical phase of the final arguments of the trial.