Police arrest a man during a child pornography raid in Melbourne. Credit:Victoria Police The police action signified a shift in strategy in investigating child abuse in Victoria, with collective raids normally reserved for drugs and gun crime, Mr Patton said. “This is the new frontline,” he said. “These are not simply online choices made for sexual gratification – they are abhorrent crimes against children, the most vulnerable people in our community.” The enormous amount of abuse material being shared every month is partly driving this change.

The true figure was probably significantly higher than 4 million, given one file could contain hundreds of others, police said. The anti-child exploitation team had already conducted a 90-day snapshot of child abuse files in 2015 that showed as many as 4000 Victorians were sharing such images online at any moment. Police found thousands of disturbing images on hard drives seized during the raids. Credit:Victoria Police The 20 men arrested have little in common apart from using the same peer-to-peer networking sites, police allege. The youngest was 19, the oldest 62, but most were in their 30s. Some work in hospitality, another in education, while others were unemployed. “Some of these people have been offending since they were 16 years old and continue to offend by looking at this material over a number of years,” Mr Patton said.

Deputy Commissioner Shane Patton Credit:Chris Hopkins “Part of this operation was focused on establishing whether any of those arrested had moved from online offences to contacting offending, and if there were any children currently at risk or who could be identified as victims of a sexual assault.” Material from the hard drives will be run through international law enforcement databases, as well as the Australian Federal Police’s victim identification library, which compares images with those held in the library to determine if they are new victims or ones known to police. Child sex dolls were also seized in the raids, police said. Peer-to-peer file sharing is when digital media is distributed over a network – like the systems used to illegally download music or movies – allowing computers to exchange files without going through a central server.

One of the 20 men arrested during the recent raids. Credit:Victoria Police It saves time and space on hard drives, but for police investigating paedophiles who are widely using this method to share material, it’s harder to trace. The files are downloaded from different computers within the network and once the download is complete, one computer becomes the source for the file, which hides its lineage. Mr Patton would not discuss the methodology officers used to locate the men, but said detectives would continue to target those sharing or accessing child abuse material on peer-to-peer networks as well as through other known methods. He said more resources – both in terms of the number of officers as well as technology – was being poured into tracking those downloading, viewing and sharing child abuse material. “People who are sitting in their suburban homes and thinking they’re not going to get caught, well, this is putting them on notice,” Mr Patton said.