Security Service of Ukraine took into custody a threat actor known as Sanix, who they claim posted 773 million e-mail addresses and 21 million unique passwords on a hacker forum last year. Authorities seized computer equipment with 2 terabytes of stolen information along with phones that show evidence of illegal activities, as well as about $10,000 in cash from illegal transactions in both Ukrainian hryvnias and U.S. dollars. The database of breached emails was discovered on a popular underground hacking forum on Jan. 17, 2019.
Source: https://threatpost.com/alleged-hacker-behind-massive-collection-1-data-dump-arrested/155915/