Retired military officer and two others killed in suspected drug cartel killing near Mexican city of Cancun.

The three, who were found dead in the back of a truck, were part of a protection team for Cancun's mayor.

Authorities say they think the men were intercepted on a road near Cancun, then taken to a remote forest, tortured, and killed with a shot to the head.

Drug related violence claimed more than 5,000 lives in Mexico last year.

Brig Gen Mauro Enrique Tello had only just become a security consultant, having retired from the army on 1 January.

The investigation is ongoing, but Cancun's local prosecutor has already said that the nature of the murders and the identity of the victims points to a contract killing by a drug cartel, the BBC's Stephen Gibbs reports from Mexico City.

The Mexican government, which depends on tourism income, will be determined to ensure that this is an isolated case, he says.

Drug related violence in Mexico is soaring, as criminal gangs fight both each other and federal forces as they battle to control the immensely lucrative routes trafficking cocaine and other drugs from Colombia to the US.

But most of the violence has been to date been concentrated in Mexico's Northern border cities.

Cancun, which attracts millions of tourists every year, has largely been spared.

President Felipe Calderon has vowed to destroy the cartels that make billions of dollars trafficking cocaine and other drugs to the United States.