North Korean hackers are increasingly focusing their criminal activity on the world of cryptocurrency and have recently built malicious cryptocurrency apps, launched ransomware attacks, and even promoted a fraudulent initial coin offering in pursuit of digital cash, the Justice Department said Wednesday.

Federal prosecutors provided the new details in a grand jury indictment returned in December and unsealed on Wednesday, charging two alleged members of North Korea’s military intelligence services, Jon Chang Hyok and Kim Il, with a wide-ranging scheme that included attempts to steal $1.3 billion over the past half-decade for Pyongyang.

A third man, Park Jin Hyok, who is also named in the indictment, was previously charged in a September 2018 case that accused him of playing a role in the 2016 theft of $81 million from Bangladesh’s account at the Federal Reserve Bank of New York and the 2014 Sony Pictures hack, among other intrusions.

The hackers also allegedly sent spear phishing emails to employees at the State and Defense Departments and multiple U.S. technology companies in January and February 2020, the indictment said.

The charges chronicle a criminal moneymaking operation that has mirrored the general public’s increasing interest in digital currencies, as bitcoin has topped the $50,000 mark.