Daniel Walker became an undercover investigator to save women and children from being sold into sex slavery.
His mission ended in a mistake that cost him his marriage and made him question his identity.
The former detective took up a job in 2002 with a private US organisation that infiltrates brothels suspected of coercing children into prostitution.
Over the next four years his undercover work helped save hundreds of children – some as young as five – from being forced to work in brothels.
But he would never have accepted the job if he had known the toll it would take on him and his family.
“Indeed, had I glimpsed just a little of the suffering I would witness and the heartbreak I would endure, I would have fled in the other direction,” he writes in his book, God in a Brothel: An Undercover Journey in Sex Trafficking and Rescue.
Source: NZ Herald