A 32-year-old Australian "computer geek" has been arrested on suspicion of building an encrypted messaging app used by hundreds of criminals worldwide to arrange drug deals and order killings, local police said Wednesday.
Australian Federal Police said the app -- known as Ghost -- was marketed to underworld figures as "unhackable" and was used by hundreds of suspected criminals from Europe, the Middle East and Asia.
But, unbeknownst to users, global policing authorities had hacked the network and were watching as the criminals discussed trafficking illicit drugs, money laundering, homicides and serious violence.
Authorities finally made their move on Tuesday and Wednesday, arresting criminals from Italy, Ireland, Sweden, Canada and Australia -- including the 32-year-old "mastermind" of the app.
Europol executive director Catherine De Bolle said law enforcement from nine countries had been involved in the international sting.
"Today we have made it clear that no matter how hidden criminal networks think they are, they can't evade our collective effort," she said.
The policing agency is expected to provide an update on the matter on Wednesday.
The Ghost app -- a kind of WhatsApp for criminals -- was created nine years ago and could only be accessed via modified smartphones that sold for about Aus$2,350 (US$1,590).
The hefty price tag included a six-month subscription to the Ghost app and tech support, Australian police said Wednesday, and users were required to purchase an ongoing subscription.
French police traced the creator's location to Australia and joined forces with local police to target the platform.
The app's creator regularly pushed out software updates but in 2022, Australian police were able to hijack those updates to access encrypted content.
For two years, authorities watched as Ghost became more popular and criminals exchanged messages -- including 50 death threats which Australian police said they were able to thwart.
There were 376 phones with the Ghost app installed in Australia alone.
In one case, police intercepted an image of a gun to someone's head and were able to save that person within the hour, Australian Federal Police assistant commissioner Kirsty Schofield said.
The force's deputy commissioner, Ian McCartney, said Wednesday it was "a particularly serious challenge" for law enforcement to get access to encrypted messages.
Hacking into encrypted apps on cell phones has become increasingly challenging for authorities, but not impossible.
Three years ago, a similar network -- called ANOM -- led to 800 people arrested worldwide.
Little did they know, ANOM was produced and distributed by the FBI, allowing US and other nations' law enforcement to decrypt 27 million messages, many of which related to criminal activity.
McCartney said after the ANOM network unraveled, Ghost started to "fill that space".
He added law enforcement was aware of other similar encrypted apps and said he hoped some of these would be shut down within 12 months.
McCartney said the Ghost app creator from New South Wales lived at home with his parents and did not have a criminal history.
The "computer geek" was driven by profit and was "slightly surprised" when police arrested him Tuesday, McCartney said.
Schofield added that police had to act quickly given the man had the ability to "wipe the communications on the system".
"Our tactical teams were able to secure him and the devices within 30 seconds of entry," she said.
The 32-year-old man was charged with five offences, including supporting a criminal organisation, which carries a sentence of up to three years imprisonment.
Another 38 people have been arrested across Australia.