Three more suspected members of the Los Zetas drug cartel were arrested in the northern Mexican state of Nuevo Leon in connection with the Aug. 25 arson attack that killed 52 people at Monterrey's Casino Royale, police said.

Jose Alberto Loera Rodriguez, "who had approximately 40 suspected criminals at his service" as lookouts at strategic locations across Monterrey "to warn him of the movements of the authorities and rival groups" was arrested on Tuesday, Federal Police regional security division chief Luis Cardenas Palomino said.

The 28-year-old Loera Rodriguez is suspected of being one of the planners of the attack on the casino, an incident that President Felipe Calderon labeled a "terrorist" act.

Loera Rodriguez "was the one who allegedly was in charge of carrying out the surveillance around the casino," Cardenas Palomino said in a press conference.

Authorities were offering a reward of 15 million pesos ($1.07 million) for information leading to the capture of Loera Rodriguez, one of the four Los Zetas leaders who intelligence reports say organized the attack, the Public Safety Secretariat said.

Suspected cartel members Hector Javier Montoya Chavez, 25, and Juan Antonio Melendez Suarez, 36, were arrested along with Loera Rodriguez.

Police seized 15 rifles, two grenade launchers, two grenades, 192 ammunition clips, 2,400 rounds of ammunition and other equipment from the suspects.

The three suspects were handed over to the Siedo organized crime unit of the Attorney General's Office for prosecution.

Los Zetas gunmen torched the Casino Royale because the gaming establishment's owner reportedly refused to pay protection money in an extortion racket the gang was running.

The gunmen told the people inside the casino to get out before setting fire to the building.

The majority of the 52 victims died from smoke inhalation, with only seven burning to death.

The fire exits were closed and the casino lacked fire retardant materials, allowing the fire to spread quickly.

The attack on the gambling establishment unearthed a web of corruption involving officials and casino owners.

Owners of some Nuevo Leon casinos have complained that they are subjected to extortion by organized crime elements and also by officials, who threaten to shutter their establishments if payments are not made.

Manuel Jonas Larrazabal, the brother of Monterrey's mayor, was arrested on Sept. 1 by the Nuevo Leon Attorney General's Office after several videos were posted on the Reforma newspaper's Web site showing him receiving cash during visits to casinos.

His defense attorney said the money was payment for the sale of "cheeses and mescal (a distilled alcoholic beverage)" from the southern state of Oaxaca to people linked to casinos in Monterrey.

One of the videos was dated Aug. 19, just six days before the torching of the Casino Royale.

Reports came out after the attack that the casino lacked an operating license, officials did nothing to close it despite the lack of basic safety systems and judges allowed the gaming establishment to continue in business.

Calderon ordered an extensive investigation of Mexico's casinos in the wake of the fire in Monterrey.

Many of the country's casinos operate in an irregular manner, with some staying open for business due to controversial court orders.