``Oswal was no doubt killed by the ULFA but only a thorough investigation will be able to confirm whether the ISI too had a role in it,'' Advani said at a Press conference while wrapping up his two-day tour of Assam.

Oswal, he said, was kidnapped for money and was ultimately killed because the ransom was not paid. ``But whether he was negotiating with the ULFA over the ransom amount is only police information. I do not have evidence to prove that,'' he added.

The Home Minister said the killing of a candidate disturbs the poll process which ``is the intention of the ULFA as well as the ISI''.

``Luckily, the ISI has not been able to disrupt the electionsto the extent the government had expected, especially in the wake of the Kargil conflict where most of our security forces were diverted,'' Advani said. He said that the ISI had caused problems in Kashmir, where BJP candidate Hyder Noorani was killed in Anantnag. It had also affected the polling percentage. He said that the ISI began to grow in strength following the 1971 defeat of Pakistan in the hands of India, with the then Pakistan president Zia-ul-Haq drawing up a systematic plan to disturb India.

He then went on to blame the successive Congress and United Front governments, saying that it was during their tenures that the ISI could spread its tentacles to different parts of the country.

Interestingly, Advani refrained from blaming the Asom Gana Parishad (AGP)-led government in Assam for the Oswal murder. Dismissing Congress president Sonia Gandhi's demand for imposition of President's Rule in the state, he said: ``Any state government should be dismissed only in extreme cases.'' Advani said theCongress was facing a leadership crisis and was confused over the concept of coalition as it claimed that the alliance government would fail.

``The Congress says that coalition government would not last while the party itself was forging alliances with parties as the AIDMK, Bihar's RJD and the Republican Party in various states,'' Advani said.