The late Pablo Escobar. About 2½ years ago, several men with ties to Mexico, the US and Guatemala quietly got to work in NSW. One source describes the men as "extremely well-financed and organised". They had access to existing company structures and infrastructure and a belief that by using certain technology, they could communicate among themselves, and to their friends overseas, without detection. Before long, their business was up and running. Police believe that each month, a shipment of cocaine - anywhere between a quarter to three-quarters of a tonne - would arrive in Australia and be distributed to various criminal networks. Well-placed sources estimate that for the past 30 months, this enterprise supplied up to half the cocaine used on Australia's east coast. This belief is backed up by research by the NSW Bureau of Crime Statistics and Research, which last month estimated cocaine use in the state had increased by more than 50 per cent in the past two years.

''The market for cocaine is growing at an exponential rate and, if the price of the drug is staying the same, then this is the sign of a thriving market,'' the bureau's director, Don Weatherburn, told the Herald recently. ''It is safe to say we are in a cocaine epidemic.'' What has not been known publicly - until now - is that the suppliers of most of this cocaine are linked to Mexico's most powerful and ruthless drug cartel. In bars and nightclubs across Mexico in the country's drug hot-spots, musicians who are often paid by the cartels belt out what are known as ''narco-corridos'' - songs that glorify the drug lords. The popularity of the music is increasing. In the Mexican state of Sinaloa, these ballads mostly concern the life of Mexico's most wanted man, Joaquin Archivaldo Guzman Lorea, or, as he is commonly known, ''El Chapo'' (a nickname reflecting his short, squat build).

El Chapo was born into a peasant family in Sinaloa in 1957. The cartel he would one day lead rose to power in the 1970s and '80s under the guidance of Miguel Angel Felix Gallardo, who is more commonly known as ''El Padrino'' - Spanish for the Godfather. By the '80s, El Padrino was in charge of a syndicate that trafficked into the US cocaine supplied by the infamous Colombian Medellin cartel, run by Pablo Escobar. El Chapo began his professional career as a low-level drug courier but, thanks to his ruthlessness and cunning, became one of El Padrino's key lieutenants. In 1993, El Chapo was arrested and served eight years in jail. He escaped from prison in 2001 in a laundry basket and began consolidating the Sinaloa cartel's national and international reach. In 1989, Pablo Escobar was ranked on the Forbes rich list as the seventh wealthiest man in the world. Last year, El Chapo, who by then was considered the head of the Sinaloa cartel, was estimated by Forbes to be worth $US1 billion, making him the 701st richest man on the globe. Recently, the US Secretary of State, Hillary Clinton, compared Mexico's woes to those faced by Colombia in the '80s, a period in which the Medellin cartel exercised huge power by ruthlessly murdering, or corrupting, all who stood in its way. The murderous ways of El Chapo's cartel, and those it competes with in Mexico, sustain Clinton's comparison: Mexico is in crisis.

Since 2006, when Mexico's President, Felipe Calderon, ordered 50,000 soldiers to join the police in a drug war, more than 28,000 Mexicans have died. A favourite saying in Mexico is that the country must make a choice between silver or lead. It is a choice faced daily by police officers, journalists, politicians and the military. The same goes for the farmers and workers co-opted as drug growers and mules by the cartels. They can take the cartel's drug money or be shot. Many choose the silver; scores of high-ranking officials, including the head of Interpol in Mexico, have been arrested for taking bribes from the cartels. But many more have been murdered for refusing. The recent shooting of the mayor of a town in northern Mexico, Alexander Lopez, as he sat at his desk brought to three the number of politicians slain in the past month. Mexico's drug cartels are estimated to earn up to $40 billion a year, primarily by transporting cocaine and marijuana to distribution networks in the US and Europe. And now to Australia. Late last year NSW and federal police officers began working on intercepting an import to Australia by figures linked to El Chapo's cartel. In May, police intelligence suggested a shipment was en route from Mexico. When the suspect container arrived at the Port of Melbourne in June, customs and federal police agents found 240 kilograms of cocaine hidden in paving tiles. They switched it with an inert substance and then watched as the consignment was delivered to a suburban Melbourne warehouse and then onto a truck bound for Sydney.

After the tiles were delivered to an address in Baulkham Hills, police swooped, arresting four men, including two of Mexican or South American heritage. Four men were later charged. The key to the success of this bust was the co-operation of often wary state and federal policing agencies, as well as assistance from the US Drug Enforcement Agency. At the time of the arrests, the head of the NSW Police organised crime directorate, Detective Chief Superintendent Ken McKay, said police were still hunting for the organisers of the drug operation. ''There's a number of people very hopeful of this importation being successful. This will hurt them,'' Superintendent McKay told reporters at a press conference in July. In reality, it is unclear how much damage will be inflicted on the Sinaloa cartel and its Australian runners as a result of the bust. Loading

The co-operation and wealth of borderless organised crime syndicates present the biggest challenge for policing agencies, who face a range of obstacles: inter-agency jealousy, limited resources and reactive directives from federal and state governments. The scale of this policing challenge was hinted at by Superintendent McKay when he announced the Mexican-linked drug bust in July. "Until the head's taken off, it's never over. These people will come back at us,'' he said. ''The profit margins are too great not to.''