Mexico's rampant drug violence rocks Cancun

The azure tranquillity of Cancun, Mexico's most popular holiday destination, was shattered this week when gunmen shot and killed a prominent federal official who had recently led an investigation into local agents accused of ties with drug traffickers.

Police officials said that the investigator, Sam Rodriguez, was leaving his office late on Tuesday night when gunmen opened fire on his car, which was also carrying his wife and eight-year-old son, both of whom were unhurt. Mr Rodriguez was shot once in his car and three more times as he tried to run away.

The killing is another sign of drugs-related violence spiralling out of control in Mexico. According to the El Universal newspaper, more than 1,000 people were killed across the country in the first six months of this year, during which turf wars between rival trafficking gangs have intensified.

While most of the bloodshed has been in northern states close to the border with the US, there is growing concern that the worsening violence will inflict serious damage on Mexico's vital tourist industry.

Cancun, with its clear waters and white sand, attracts 4.6 million tourists a year and generates revenues in excess of $3bn (£1.6bn), about a third of the country's total tourist revenue. Unknown to most visitors, however, the low-lying Yucatan peninsula, dotted with major Mayan ruins and Spanish colonial towns, has become a key dropping-off zone for Colombian smugglers moving cocaine from South America towards the US.

Police in Cancun believe that Mr Rodriguez was killed because of his efforts to expose the activities of the cartels in the region. After three federal agents and two police informants were found dead in Cancun in 2004, Mr Rodriguez led an investigation that eventually resulted in the arrest of 27 state, federal and local police.

In 2001, police arrested a former governor of Quintana Roo state, Mario Villanueva, where Cancun is located. The US is still trying to extradite Mr Villanueva in the belief that he protected shipments of more than 200 tons of cocaine through his state in the 1990s when he was in office.

Acapulco, the so-called "Pearl of the Pacific" on the other side of the country, has meanwhile suffered an unprecedented spasm of violence this summer, with bodies turning up almost every week. Police there blame a deepening rivalry between two cartels struggling to control the flow of narcotics to the borders with California, Arizona and Texas.

The city ­ which saw its heyday as a ritzy destination for honeymooners and Hollywood stars in the Fifties and Sixties ­ was horrified in June when a severed head was carried by a wave and dumped on a beach next to a Mexican sunbather and her two children. Police there have recorded six beheadings this year, as well as numerous other execution-style killings and grenade attacks.

Containing the drug wars and confronting corruption in the police force has become a major political issue in Mexico, and will be a defining challenge for whoever emerges as the final winner of the country's presidential election, on 2 July, the outcome of which is still being contested.