Media are reporting that U.S. authorities will shortly issue criminal indictments against four people, three of them in Russia, in connection with massive hacking attacks on Yahoo that were the largest ever reported.
Reuters and Bloomberg, citing anonymous officials, said the U.S. Justice Department announcement could come as early as March 15.
The accused men live in Russia and Canada, with the Canadian far more likely to face arrest since Russia has no extradition treaty with the United States.
Yahoo disclosed in September the theft of personal data from more than 500 million user accounts in a 2014 hacking. In December, the company admitted to another cyberattack in 2013 that affected more than a billion users.
They were the two largest hacks in history, and the pioneering Silicon Valley firm admitted it mishandled them.
Late that year, senior executives and some legal staff were told that "a state-sponsored actor had accessed certain user accounts" by exploiting an account-management tool, Yahoo said in a recent regulatory filing.
"While significant additional security measures were implemented in response to those incidents, it appears certain senior executives did not properly comprehend or investigate," it said.