In a nutshell: Nobody wants to be spied on, especially criminals. That's where EncroChat came in. The company provided specially altered phones that let buyers use an encrypted network for exchanging incriminating messages without the risk of being seen by authorities. Or so they thought.

EncroChat's custom phones cost around $1,100, but that flagship price didn't get you flagship features; these modified Android handsets lacked cameras, microphones, and GPS. What they did offer, however, were encrypted messaging and calls, self-destructing texts, and a PIN-based "panic wipe" function. Users could even boot into the standard Android OS if they didn't want to raise suspicions, switching to the EncroChat system to access the secure features. The network also provided subscriptions with global coverage for $1,600 per month, according to the New York Times.

The UK's National Crime Agency (NCA) writes that EncroChat's instant messaging service was used by 60,000 people worldwide for coordinating the distribution of illicit goods, money laundering, and plotting to kill rivals.

What the criminals using EncroChat didn't know was that French authorities had hacked their way into the network and installed a tool allowing them to read users' communications for months. The messages were then shared with agencies around Europe.

The information led to the UK's largest-ever law enforcement operation, resulting in 746 arrests, the seizure of £54 million ($68 million) in cash, 77 firearms and more than two tons of drugs. Police also seized sub-machine guns, handguns, four grenades, an AK47 assault rifle, and more than 1,800 rounds of ammunition.

The NCA added that 28 million Etizolam pills (street Valium) were seized, along with 55 high-value cars, and 73 luxury watches. The agency worked with police to stop rival gangs carrying out kidnappings and executions by "successfully mitigating over 200 threats to life."

It was a similar story in the Netherlands, where police made 60 arrests, seized 22,000 pounds of cocaine, 154 pounds of heroin, and 3,300 pounds of crystal methamphetamine, among other substances. They also dismantled 19 synthetic drug labs, seized 25 vehicles with "special compartments," and "expensive watches."

"What seems to be possible only in police thrillers and movies has happened before our own eyes," said Andy Kraag, head of the National Criminal Investigations Department in the Netherlands. "We've captured messages that give us a view of daily life in the criminal world."

The investigation into EncroChat began in 2017. French authorities discovered the company's servers in Lille, a city in the north of France. Users were warned that the network had been "infiltrated" by "governmental entities" on June 13.

EncroChat framed itself as a legitimate company offering secure communication to those who need it, such as security professionals, lawyers, and investigative journalists. But French authorities say 90 percent of the company's customers in the country were "engaged in criminal activity." EncroChat has now shut down.

Image credit: Tero Vesalainen