The police are now certain that it was either a Thai or a foreigner who was the 'backpack man'.
That said, it does look like it was an intra-Thailand-Military/Regime/Aristocracy (not 'political' per se, no red-shirt or muslim insurgents involved; strictly a Thai military/factional turf-war) "message" which was sent, and received, so things should be fine as long as the message is acknowledged and acted upon. Things should be quiet, for a while, until they aren't.
I wouldn't expect any perpetrators to be captured, alive. Probably roll up a few patsies in a shallow grave in a mango swamp in Nakhon Nowhere?
Bomb technique was 'taught by foreigners'
NVESTIGATORS believe that the plotters behind the Erawan Shrine and Sathorn pier blasts might have relied on a foreign bomb-making technique, an informed source said.
"Such a technique did not exist in Thailand before. And our in-depth investigations reveal that foreigners of unknown nationality came to Thailand in 2011 to provide training on such a technique," the source said.
http://www.nationmultimedia.com/nati...-30267216.html
In the above article, the attempted disposal of a second bomb at Sathorn Pier suggests higher authorities called off subsequent bombs, for any number of reasons which can be speculated upon.