The tiniest of clues can sometimes catch the biggest monsters.
And few in the world are more adept at catching online pedophiles, a task which requires painstaking and horrifically confronting work, than a specialist police unit in Australia.
Queensland Police's Taskforce Argos leads the world in hunting pedophiles who film and photograph sexual abuse of children and then share that content in the darkest corners of the internet.
Taskforce Argos and Australian Federal Police officers last month joined a two-week international operation, poring over the most sickening footage imaginable, hoping to identify a location where abuse of minors is happening so that a child can be rescued.
The vast Europol operation involving 19 countries led to six victims of child abuse being successfully identified and removed from harm.
"Participation in Europol's Victim Identification Taskforce is one way Argos investigators share their expertise," a Queensland Police spokesperson told 9news.com.au.
"The outcomes highlight the importance of international law enforcement cooperation in responding to the global nature of Internet-facilitated child sexual abuse offending."
Sadly, Europol has over 59 million unique images and video files in its child sexual abuse dedicated repository.
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To prepare for its worldwide June operation, Europol specialists selected footage of child abuse victims whose location and identity had not yet been established.
As part of a team of 41 specialist detectives, QPS Argos and AFP officers helped assess over 300 documented series of abuse, including film and photos.
Eagle-eyed detectives zeroed in on accents and seemingly obscure background detail in footage, like tags on clothing, barcodes on household items, a poster on a wall or the sound on a television or radio show.
In 47 cases, a likely country of production was identified and law enforcement in those jurisdictions was alerted.
As part of its efforts to catch pedophiles and stop child abuse material, Europol regularly makes public photographs of some evidence to catch offenders and rescue victims.
Non-confrontational details of images extracted from child sexual abuse cold cases are made public in the hope that someone recognises a detail to narrow down the location of the victim.
The Europol initiative is called Trace an Object.
Since its launch in 2017, 12 children victim of child sexual abuse have been identified and removed from harm, and four offenders have been prosecuted.
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Taskforce Argos detectives have busted open many cold cases, and are regularly called on by global law enforcement bodies for help in this most difficult arena of policing.
In the last year alone, their work has led to the identification of 201 children in circumstances of sexual harm, nationally and internationally.
Forty-nine child sex offenders have been arrested and hit with 402 criminal charges in the same period, because of Argos.
The crack Australian unit has referred 690 cases to law enforcement agencies in Australia and around the world in the last year alone.
