The reports of explosions may have been the sound of the ignition of the liquid. Authorities commandeered backhoes from a nearby construction site and made a brief attempt to break into the casino's walls as smoke billowed from the main entrance, hindering firefighters. Monterrey Mayor Fernando Larrazabal said many of the bodies were found inside the casino's bathrooms, where employees and customers had locked themselves to escape the gunmen. The Attorney General's Office says in a statement that Calderon instructed authorities to offer the reward to find those responsible for what he called "an act of barbarism. Cartels often extort casinos and other businesses, threatening to attack them or burn them to the ground if they refuse to pay. Gunmen struck it and three other casinos on May 25, spraying the building with bullets, but no was reported injured in that attack. Santiago Loera, 53, went to the morgue looking for his brother, Miguel Angel, a cook at another casino who had gone to the Casino Royale to sign a new contract. Norma Reyes, 45, was one of the people who received good news Thursday. Calderon tweeted that the attack was "an abhorrent act of terror and barbarism" that requires "all of us to persevere in the fight against these unscrupulous criminal bands. She was hoping for word of her brother, year-old Genaro Navarro Vega, who had worked in the casino's bingo area. Navarro said she tried calling her brother's cell phone. Medina lowered the death toll to 52 early Friday. They are also seen carrying three large bottles, which Gov. Her son called her before she even heard about the fire to say he was all right. Two dozen gunmen burst into the casino in northern Mexico on Thursday, doused it with a flammable liquid and started a fire that trapped gamblers inside, killing more than 28 people and injuring a dozen more, authorities said. Surveillance video shows at least eight assailants arriving to the Casino Royale in four cars and heading to the main entrance. Two dozen gunmen burst into the casino in northern Mexico on Thursday, doused it with a flammable liquid Caption Close. Rodrigo Medina said probably contained gasoline. De la Garza said the liquid appeared to be gasoline. Jonathan Reyes, 25, who worked as an area supervisor, told his mother he was at the hospital trying to find out what happened to his co-workers. Once Mexico's symbol of development and prosperity, the city is seeing this year's drug-related murders on a pace to double last year's and triple those of the year before. Most Popular.{/INSERTKEYS}{/PARAGRAPH} Last month, gunmen killed 20 people at a bar in Monterrey. State police officials initially said witnesses reported hearing three explosions before Thursday's fire started, but later said a flammable material was used. Maria Tomas Navarro, 42, stood weeping at the edge of the police tape stretched in front of the smoke-stained casino building. Image 1 of Back to Gallery. It was the second time in three months that the Casino Royale was targeted. The attackers sprayed the bar with rounds from assault rifles, and police later found bags of drugs at the bar. The officials were not authorized to be quoted by name for security reasons. Two dozen gunmen burst into the casino in northern Mexico on Thursday, doused it with a flammable liquid. {PARAGRAPH}{INSERTKEYS}But many of the terrified victims fled farther inside the building, where they died trapped amid the flames and thick smoke that soon billowed out of the building. Calderon described the incident as the worst attack on innocent civilians in recent memory. He had said late Thursday 53 people had died in the fire at the Casino Royale. Loera said authorities have asked him for a DNA sample. The fire in the two-story casino, which advertised sports book and bingo, was reported just before 4 p. EDT; GMT , a slow time of day when normally about 80 people played the tables and slots, said former security guard Alberto Martinez Alvarado, Martinez, who was on his way home from work Thursday when he saw the fire, said the casino could hold hundreds, perhaps 1, people. Family members arrived at the morgue all through the night in Monterrey, a modern metropolis and one of Mexico's most important business centers that has been the scene of a ferocious turf battle between the Gulf and Zetas drug cartels. I don't know what is happening," she said.