BANGKOK (AP) — It's a whodunit worthy of a Dan Brown novel: a small bronze plaque commemorating Thailand's 1932 revolution is ripped out from a very public place by parties unknown and substituted by one praising the Chakri Dynasty, whose 10th king took the throne in December. The original plaque, installed in 1936, marked the spot where a group of progressive army officers and civil servants proclaimed the end of the absolute monarchy in order to steer the country toward democracy. A royalist military government that took power in a coup three years ago still rules Thailand, and its newly enacted constitution aims to limit the power of elected officials and give it instead to institutions traditionally associated with the palace, including the courts, the civil service and the military. The old plaque, about 30 centimeters (12 inches) in diameter and lying flush with the pavement, was embedded in Bangkok's Royal Plaza, a vast open area in the midst of government buildings and military installations. Debate on social media over the plaque's disappearance has evoked a strong streak of antidemocratic sentiment, decrying the 1932 revolution for imposing unsuitable Western-style democracy causing corruption and all sorts of social ills; slamming the 1932 coup makers as evil; and even suggesting that the plaque was the physical incarnation of a curse on the nation. Thaksin, accused of corruption, abuse of power and disrespect for the monarchy, was ousted by a military coup in 2006, setting off a sometimes violent struggle for power between his supporters and opponents, with the military strongly in the latter group.