In 2008, Ecuadorian security forces seized $545,000 being illegally smuggled across its borders, according to figures collected for a report by El Comercio. By 2012, these seizure numbers had risen to $1.9 million and 215,000 Euros. Throughout the entire period, authorities seized over $10 million, 4 millon Euros (approximately $5 million) and smaller quantities of pesos from Colombia, Chile, Cuba and the Dominican Republic.

Police arrested 79 people for cash smuggling at Quito and Guayaquil airports over that same time period. However, although 70 criminal cases were opened, only six resulted in convictions, while 18 people were acquitted and 28 of the cases were dismissed. Police estimate that for every one person they capture, five more make it across the border safely.

Cases have been hampered by fuzzily defined legal requirements for prosecutors to prove the illicit origins of the money. Judges have also been inconsistent in their interpretation of the laws.

El Comercio, for instance, chronicles the case of three Ecuadorians, who were arrested in Quito airport in 2011, coming from the Netherlands with 180,000 Euros each, hidden in their crotches. They were convicted of money laundering, but the ruling was overturned on appeal after a judge determined prosecutors had not adequately shown the origins of the cash. The money was returned to the men, minus a 30 percent fine for not declaring it.

The figures cited above do not include seizures made by Ecuador's Customs Service, which, according to an off-the-record source consulted by El Comercio, made 50 more stops. However, customs officials were powerless to do anything except fine the smugglers 30 percent of the haul and return the rest of the cash.

According to an anonymous police investigator cited by El Comercio, while over 90 percent of the money was seized at the country's airports, cash smuggling by air represents just a fraction of the money smuggled in and out of Ecuador. The majority, the source says, is moved across land and maritime borders, where it is more difficult to effectively monitor crossings.

InSight Crime Analysis

According to US law enforcement agencies, criminal organizations have increasingly turned to bulk cash smuggling as a result of the crackdown on money laundering operations through the established financial industry.

There are two principal methods used to smuggle cash. One is bulk shipments in commercial vehicles, the other is the "ruta hormiga," or "ant route," which sees cash shipments broken down, smuggled across the border by individuals carrying $5,000-10,000, then reconsolidated on the other side.

According to a 2010 Woodrow Wilson institute study into Mexican cartel's cash smuggling operations, cash smuggling may be "in-sourced" -- managed internally by cartel members -- or "outsourced" -- contracted out to independent smugglers or money brokers.

Most seizures occur at airports but, as suggested by the Ecuadorian police, this is likely a reflection of better facilities for checking baggage rather than an indication it is a more popular route.

Cash smuggling routes generally follow the same paths taken by drugs but in reverse, frequently using the same personnel, contacts and transport infrastructure. As such, by far and away the most popular route with drug traffickers is crossing the Mexico–United States border, where estimates for the amount of cash smuggled vary wildly -- from $6 billion to $36 billion a year, according to the Wilson Center report.

However, evolutions in both drug trafficking and money laundering are popularizing other transit routes as well -- including through Ecuador. According to the Wilson Center report, Mexican cartels increasingly look to bypass their home country when moving money that will be reinvested in paying for more cocaine, instead moving the cash to Colombia and Ecuador. To do this the cartels sometimes use international criminal groups based in Russia and China as smugglers.

This method has helped Mexican cartels cut out the middle-men who move drugs into Mexico and purchase cocaine closer to the source. This includes Ecuador, where the guerrillas of the Revolutionary Armed Forces of Colombia (FARC) -- who manage much of the cocaine distribution chain in Colombia but have little to do with exports -- have a strong presence and can sell cocaine cultivated and processed in the south of Colombia.

The United States has responded to the growth in cash smuggling with stronger legislation. In the 2001 Patriot Act, the government criminalized international bulk cash smuggling for amounts over $10,000, introducing sentences of up to five years imprisonment and provisions for the seizure of all cash and goods discovered at the time or traced to the operation.

Responsibility for enforcing the new legislation fell to the Immigration and Customs Enforcement agency (ICE), which established the National Bulk Cash Smuggling Center. From the fiscal year of 2003 to 2010, ICE agents seized over $500 million dollars -- nearly 20 percent of which came in 2010 -- and arrested over 1,300 people.

In 2005, ICE, along with the Customs and Border Protection agency (CBP) launched "Operation Firewall," which targets cash smuggling in the United States and works with international partners abroad.

The US approach goes some way to closing the legal loopholes that have seen cash smugglers in Ecuador not only escape unpunished but also with much of the money. However, while cracking down on cash smuggling may disrupt cartels' revenue streams, it leaves their operational capacity barely touched, as arrests are unlikely to ever move beyond mules -- the bottom rung of the drug trafficking chain.

Meanwhile, the cartels continue to evolve. As low tech methods such as cash smuggling and pre-paid cards have grown in popularity, there are signs that so has the use of new money laundering techniques that instead focus on opportunities to be found in an increasingly high tech and connected world, underscoring the Sisyphean nature of stopping the flows of drugs and cash.