One of the men believed to have been responsible for the deadly arson attack on a casino in Monterrey, Mexico, has been killed.

Francisco Medina Mejia, one of the key suspects in the August 25 attack on the Casino Royale that resulted in the deaths of 52 people, was killed in a gun battle with soldiers near the border with Texas. Three other gunmen were killed in the incident.

Mejia was alleged to have been a key figure within the Zetas drug cartel, an organisation the authorities believe was behind the Casino Royale attack, which saw gang members burst into the casino before spreading gasoline and setting it alight.

Until a few years ago, Monterrey was among Mexico’s safest cities, but recent drug-related violence and organised crime have seen a dramatic increase in murders.

Some reports suggest that owners of casinos have been targeted by criminal gangs for refusing to meet their demands for protection money.