Mexicans are observing three days of mourning for the 52 people killed in an attack on a casino.<br /><br />The government is offering a reward of more than two-million dollars to find the gunmen who set the building on fire.<br /><br />President Felipe Calderon says the United States and its appetite for drugs is partly to blame.<br /><br />Al Jazeera's Franc Contreras reports from Monterrey.
