The Department of Internal Affairs has helped bust Australian paedophiles who bought a child, abused him and traded him to other paedophiles to do the same.
On Friday the man was jailed for 40 years in the US for sexually abusing a young boy, a direct result of an investigation by New Zealand's Department of Internal Affairs.
The US District Court in Indianapolis heard how the 42-year-old man bought a baby boy for $US8000 with his male partner, sexually abused the child and traded him to others to abuse.
The two men, who had been living in California, bought the newborn boy in an undisclosed country and used falsified documents in Los Angeles in an attempt to adopt him.
The boy was rescued by US authorities and is being cared for in California.
The men, who lived in Cairns, were tracked down by authorities after being tipped off by the Censorship Compliance team at Internal Affairs which investigates online child sex abuse.
The case was triggered by senior investigator Jon Peacock, who saw something suspicious about a series of photos of a six-year-old boy stored on the computer of a man in a separate investigation.
"The photos were several studio or professional shots of the boy in what appeared to be artistic poses," he said.
"However the poses and the way he looked into the camera were unusual and tipped me off that something may have been badly wrong. My first thought was I wanted to contact the boy's parents or guardians to figure out if they knew such photos were being taken."
Using clues to the boy's identity from photos and video the investigation team linked the case to Queensland and involved Australian enforcement colleagues.
Further enquiries uncovered evidence of offending and authorities in the US became involved.
The international investigation led to last week's sentencing of the boy's guardian and the man's partner has also pleaded guilty. He will be sentenced later this year.
"Rescuing and protecting children from this vile trade is what it's all about," said Peacock.
"This investigation began in the Wellington region, but the web of abuse took on an international perspective with offences being discovered in France, Germany, America, and Australia."
''For more than one year and across three continents, these men submitted this young child to some of the most heinous acts of exploitation that this office has ever seen,'' Indiana US Attorney Joe Hogsett said after the sentencing.
Mr Peacock was proud the department was building an international reputation and said cracking the case was "immensely satisfying".
- Fairfax Media