According to Nate Thayer's blog http://www.nate-thayer.com/family-murdered-journalist-accuses-canadian-government-complicit-cambodian-murder-cover/

Certainly it is clear that the official claim that there was no foul play is ludicrous. Stepped out of his guesthouse to let the maids clean it, taking nothing with him - phone, wallet etc still in the room - then vanished and body turned up quite some km away in the forest.

so to be clear, somebody writes in his blog something and it's news on TV?

Not usually, no.

But this "somebody" is a world renowned Journalist and specialist in Cambodia.

Same claims now in the major Cambodian English language paper: http://www.phnompenhpost.com/national/canadian-journalist-was-murdered-family