Mexican authorities have arrested a police officer in connection with an attack last week on a casino in the city of Monterrey that killed 52 people.
The Nuevo Leon state police officer is suspected of having taken part in an arson attack on the upmarket Casino Royale on Thursday.
Drug-related violence has claimed over 42,000 lives since President Felipe Calderon went to war on the drug cartels after taking office at the end of 2006, Reuters reports.
Five others arrested over the attack are believed to be members of the Zetas drug cartel, which has ravaged the prosperous northern city of Monterrey over the past two years.