Ketheshwaran Loganathan, Deputy Director General at the Sri Lankan government's Peace Secretariat, was shot dead by unidentified men in Colombo on Saturday.
Kethesh, as he was known in political circles, was in the Eelam Peoples' Revolutionary Liberation Front (EPRLF), a Tamil group that was opposed to the LTTE, before he took to academics and peace advocacy.
He was shot in the head at point blank range at his house in Dehiwela by a group of men who came in a van, the Sri Lankan military said.
He died on the way to the nearby Kalubowila hospital.
As one of the top leaders of the EPRLF, Kethesh participated in the talks with the Sri Lankan government held at Thimpu in Bhutan in 1985, under the auspices of the Rajiv Gandhi government.
After the collapse of the India-Lanka Accord in 1990, Kethesh left for Holland to do higher studies and research. He is the author of the book " Sri Lanka: Lost Opportunities".