Five suspects have been arrested in the investigation of an arson attack on a casino that killed 52 people in northern Mexico

Nuevo León state Gov. Rodrigo Medina tells the Televisa network that police are looking for two other suspects.

He says that police are investigating whether the attack in the city of Monterrey was in retaliation for not paying extortion money.

The governor said Monday that authorities have not yet determined what group is behind the attack.

Thursday's attack at the Casino Royale in Monterrey is one of the deadliest attacks on an entertainment center in Mexico since President Felipe Calderón launched an offensive against drug cartels in late 2006. Calderón denounced the incident as "terrorism." 

This story is based on the Associated Press. 

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino