Mexican authorities raided casinos Saturday throughout the northern town of Monterrey, two days after armed men burned a local gambling house, killing 52 civilians. Security forces have arrested three and confiscated 1,500 slot machines from 11 casinos in the area. Authorities are investigating whether or not the casinos have paid taxes or operate outside of the law—but they would not say whether or not the raids were related to the recent massacre. Thursday's arson attack differed from Mexico's ongoing murders in that upper- and middle-class civilians were targeted rather than cartel members. "We are facing true terrorists who have gone beyond all limits," said President Felipe Calderón in a nationally televised speech. No specific cartel operation has been named responsible.