An encrypted phone service called Anom was secretly run by the Federal Bureau of Investigation in a yearslong international sting operation. Law enforcement agencies across Europe, the US, and Oceania revealed Anom’s origins earlier today, saying they had arrested 800 criminal suspects based on intercepted communications.

According to public statements, the FBI and other agencies seeded secure Anom phones with suspected crime syndicates, gradually building a network of around 12,000 total (and 9,000 active) devices. The phones secretly siphoned 27 million messages between 2019 and 2021, resulting in Operation Greenlight / Trojan Shield — a large-scale bust that included seizing around eight tons of cocaine, 22 tons of cannabis and cannabis resin, 250 firearms, and $48 million in traditional currencies and cryptocurrencies.

Seamus Hughes, a George Washington University researcher, offered more details from court records. As Vice reported based on Hughes’ work, Anom started in 2018 after police shut down Phantom Secure, an encrypted device network used mostly (the FBI alleges exclusively) by drug traffickers and other organized criminals. An unnamed informant, who had previously sold Phantom Secure phones, told the FBI they were building a “next generation” encrypted device called Anom. The informant offered the system to the FBI and Australian Federal Police in exchange for a reduced sentence on criminal charges, then agreed to sell Anom phones to their existing distribution network that catered to organized crime, giving the new system credibility.

Unbeknownst to buyers, each Anom message included a “master key” that would let law enforcement decrypt its contents, and each device tied a fixed ID number to any username the owner chose. The messages secretly routed to servers that the FBI — as well as the AFP and later other police agencies — could access. A court filing cites examples of these messages, including photos of cocaine packages and conversations about how to smuggle shipments of drugs.

Most early Anom users were located in Australia. But the network ultimately covered 90 countries, with Germany, the Netherlands, Spain, Australia, and Serbia seeing the most users. Its growth surged in early 2021, when law enforcement shut down Sky Global, another encrypted messaging company. A press release from Europol says that 300 criminal syndicates used Anom devices, including “Italian organized crime, outlaw motorcycle gangs, and international drug trafficking organizations.”

Beyond direct busts made with Anom data, the FBI described Anom as a move to “shake the confidence in this entire industry” of encrypted device services. Police have tried to plant backdoors in both general-purpose and specifically crime-focused messaging services, and they’ve hijacked platforms like dark web marketplaces to catch illegal activity — but it’s rarer to see an agency help launch a brand-new phone network for the purpose.