Confusion swirls around who carried out Bangkok’s deadly bombing. But experts say the unprecedented scale of Monday’s attack and apparent targeting of tourists could indicate a game-changing escalation of tactics for the country’s usual suspects — or an entirely new threat.

Here is what we know so far about investigations into the blast, which killed 20 people and wounded more than 100 at a crowded Hindu shrine in the Thai capital.

… “Whatever the identity or motive of the perpetrators, the reality is that a threshold has been crossed, and Thai politics and society will likely take a radically different course in the months, and possibly years, to come,” anti-terror expert Joseph Liow of the Brookings Institution wrote in an essay.

… Frustration could be rising in younger militants, said terrorism analyst Rohan Gunaratna.

“If it was people from the south of Thailand, that means the landscape has changed dramatically because it would mean the conflict expanded from the south,” Gunaratna said, but he added that so far nothing indicated involvement from the insurgents.