During the course of the Sri Lankan civil war, he was killed by EPDP by poison in 1994 He was born in a town called Theldeniya (see here) in the [Kandy District to upper class minority Sri Lankan Tamil parents and grew up in Kotatadi, Jaffna.
[1] After the 1983 Black July anti-minority pogrom he briefly moved to India and was involved with the Tamil militant group Eelam People's Revolutionary Liberation Front (EPRLF).
With the resumption of hostilities between the government of Sri Lanka and the main rebel group Liberation Tigers of Tamil Eelam(LTTE) he was abducted by unknown persons and found murdered in a Colombo beach.
[2] According to a former member of a political party and a paramilitary group known as the Eelam People's Democratic Party(EPDP) which in itself was a pro government splinter group from the EPRLF that K. S. Raja was once part of, K. S. Raja was killed by orders of Douglas Devananda the leader of EPDP.
[2] When Douglas Devanada was asked about his involvement in the murder of K. S. Raja, he did not directly deny the responsibility or answer the question, instead pointed to other journalists allegedly killed by LTTE.