(Reuters) - A Canadian accused by the United States of helping Russian intelligence agents break into email accounts as part of a massive 2014 breach of Yahoo accounts pleaded guilty on Tuesday, the U.S. Justice Department said.

A photo illustration shows a Yahoo logo on a smartphone in front of a displayed cyber code and keyboard on December 15, 2016. REUTERS/Dado Ruvic/Illustration

Karim Baratov pleaded guilty to charges returned by a grand jury in the Northern District of California in February for hacking email accounts and selling the passwords to an agent of Russia’s intelligence agency, the department said in a statement.

Baratov, a 22-year-old Canadian citizen born in Kazakhstan, was arrested in Canada in March at the request of U.S. prosecutors. He later waived his right to fight a request for his extradition to the United States.

The Justice Department announced charges in March against Baratov and three other men, including two officers in Russia’s Federal Security Service, or FSB, for their roles in the 2014 theft of 500 million Yahoo accounts.

Following the charges, a spokesman for Russian President Vladimir Putin dismissed the idea that FSB employees could have been involved in the Yahoo hack.

Verizon Communications Inc, the largest U.S. wireless operator, acquired most of Yahoo Inc’s assets in June.

Prosecutors said the FSB officers, Dmitry Dokuchaev and Igor Sushchin, directed and paid hackers to obtain information and used Alexsey Belan, who is among the Federal Bureau of Investigation’s most-wanted cyber criminals, to breach Yahoo.

When the FSB officers learned that a target had a non-Yahoo email account, including through information obtained from the Yahoo hack, they worked with Baratov, who was who paid to break into at least 80 email accounts, prosecutors said.

The individuals associated with the accounts they sought to access included Russian officials, the chief executive of a metals company and a prominent banker, according to the indictment.

At least 50 of the accounts Baratov targeted were hosted by Google, the indictment said.

The Justice Department said on Tuesday that as part of his plea agreement, Baratov also admitted to hacking more than 11,000 email accounts in total for both the FSB and other customers from around 2010 until his March 2017 arrest by Canadian authorities.

Baratov, the only person arrested to date in the case, had pleaded not guilty in August to conspiring to commit computer fraud, conspiring to commit access device fraud, conspiring to commit wire fraud and aggravated identity theft.