Sitting in a police station in a small rural town in Ecuador, Mark and Jan Rodgers waited patiently to interview the local police chief.
The husband and wife team, American academics who specialised in human trafficking, had come to investigate how the dangerous combination of widespread poverty and a lack of awareness had created a fertile hunting ground for traffickers.
As they waited, three families came in one by one to report their daughters missing. Each story was disturbingly similar: the girls, all middle-school students, had not returned home from school. The police casually dismissed the families, suggesting the girls were teenage runaways.
'That was in one afternoon alone,' Professor Mark Rodgers said. 'We were flipping out, like, come on, wake up!'
They may have worked in trafficking hot spots such as Latvia and Romania, but the lack of awareness or indifference to one of the world's most profitable illegal activities continues to dismay the Rodgers.
Trading in humans is one of the world's oldest businesses, dating back to ancient times. Frequently referred to as modern-day slavery, human trafficking may officially be illegal in most parts of the world but the practice of buying and selling people for sexual or labour exploitation is thriving.
The CIA estimates that between 600,000 and 800,000 people, mostly women and children, are trafficked across national borders every year. That figure does not include the millions trafficked within their home countries, such as the slaves recently found working in atrocious conditions in brick kilns in Shanxi province . The discovery of the kiln slaves, some of them children, has revealed the dark underbelly of forced labour on the mainland, where dire poverty leaves rural villagers vulnerable to abuse.