Mexico's President Calderon has declared three days of mourning and his government is offering a $2.4 million reward for information leading to those behind a casino attack which killed over 50. Several gunmen burst into the building in Monterrey on Friday, dousing it with fuel and setting it alight. Officials suspect organized crime was behind the attack, one of the deadliest since a 2006 crackdown on drug cartels. US President Barack Obama condemned the attack, reinforcing his commitment to helping Mexico combat criminal groups. Correspondent Franc Contreras is in Monterrey.