An FBI-led sting using an encrypted messaging app has resulted in the arrests of hundreds of suspected organized crime figures around the world, authorities in Australia announced Tuesday.

Driving the news: Authorities decided to use the AN0M messaging app to track suspects globally in an investigation after Aussie police officers and FBI agents came up with the idea to run the platform while having some after-work beers in 2018, according to Australian police.

• Australian Federal Police commissioner Reece Kershaw said at a briefing Tuesday that suspected "Australian mafia, Asian crime syndicates," drug traffickers and members of outlawed motorcycle gangs, were among 224 people arrested in the country.
• Hundreds other suspects were arrested in raids in places including the U.S., Europe, Asia, South America, the Middle East and New Zealand — 18 countries in all, and more arrests were expected.

What they did: In the sting, called Operation Ironside in Australia and Trojan Shield in the U.S., authorities decrypted and tracked some 25 million messages in real-time — monitoring discussions on planned executions, massive drug importations and money laundering.

• Authorities said Australian fugitive Hakan Ayik, a suspected major drug trafficker, unknowingly helped the sting by recommending the app to associates after being given a device pre-loaded with AN0M, which was sold on the black market.
• The encryption resulted in criminals being "very brazen," with "no attempt to hide behind any kind of codified kind of conversation," according to Kershaw.
• "Essentially, they have handcuffed each other by endorsing and trusting AN0M and openly communicating on it — not knowing we were watching the entire time," he added.

By the numbers: Authorities said they prevented one planned mass shooting by an organized crime syndicate in an Australian suburb and 21 murder plots, as they seized over 3 tons of drugs and A$45 million ($35 million) in cash and assets.

• The sting was the largest operation of its kind in Australia, involving some 4,000 Australian officers, with about 9,000 law enforcement involved globally.

What they're saying: Australian Prime Minister Scott Morrison said at the briefing the operation "has struck a heavy blow against organized crime ... one that will echo around organized crime around the world."

• Kershaw said the FBI "had the lead on this," while Aussie police "provided the technical capability to decrypt those messages."
• "Some of the best ideas come over a couple of beers," he added.

What to watch: The FBI and its European counterpart Europol will announce their own findings later Tuesday, said Anthony Russo, FBI legal attaché at the U.S. Embassy in Australia.

Editor's note: This article has been updated with new details throughout.