I think the event's political opponents because he has a bomb before the event click on the video of him, he is swearing Bangkok Thailand earlier Government. He did not want the democratic system does not need to have the King of the unrest situation.
I think that political opponents. Before the bombing, because he had a video tape of his curse people who visited Thailand had been a previous government. He does not want democracy, not a monarchy. Create unrest
Thought the political events of the opponent. Because before the incident, he has said his country video bit he was a government before the page. He doesn't want democracy not a king.