The U.S. charged four people, including two Russian intelligence officers, over the theft of hundreds of millions of accounts of Yahoo Inc. users from a computer breach that threatened to derail its acquisition by Verizon Communications Inc.

The Department of Justice accused the four of theft, conspiracy, economic espionage, wire fraud and theft of trade secrets connected to one of the largest data breaches in history. 

The indictments, filed in San Francisco federal court, point to actions deep inside Russia’s intelligence machine that could give Moscow access to compromising information on users of one of the world’s biggest email platforms.

Among those charged were Dmitry Dokuchaev and Igor Sushchin, who prosecutors say worked for the Russian Federal Security Service unit that conducts cyber investigations.