MONTERREY, Mexico – Mexican troops have converged on this industrial city searching for the perpetrators of an arson fire at a casino that killed 52 people on Aug. 25.

Close to 1,500 security forces conducted raids on nearly a dozen casinos in Monterrey, detaining three people, media reported.

Mexican president Felipe Calderón ordered police and army reinforcements to Monterrey last week, while the justice ministry offered $30 million pesos (US$2.4 million) for information leading to the arrest of the attackers.

Authorities are looking into whether drug cartels had threatened the casino in an extortion plot.

In the attack, armed men, believed to be from either the Zetas or Gulf cartel, emptied cans of gasoline and set fire to the Casino Royale in the northeastern city of Monterrey, a flashpoint in their brutal turf war.

[AFP, 28/08/2011; Voice of America, 28/08/2011; CNNExpansion, 27/08/2011]