This is a meth addict trick

MONTERREY, Mexico -- Two dozen gunmen burst into a casino in northern Mexico on Thursday, doused it with gasoline and started a fire that trapped gamblers inside, killing at least 45 people and injuring a dozen more, authorities said.
The fire at the Casino Royale in Monterrey, a city that has seen a surge in drug cartel-related violence, represented one of the deadliest attacks on an entertainment center in Mexico since President Felipe Calderon launched an offensive against drug cartels in late 2006.
 http://www.sacbee.com/2011/08/25/3862171/8-dead-in-grenade-attack-on-northern.html#ixzz1W6Wlv5fV

The gang wars are not about marijuana, they are about exporting methamphetamine to the USA. Most of the cartel members live on the drug and it causes severe brain damage, resulting in violent delusions.