The Federal Bureau of Investigation is investigating the leaked emails from the Democratic National Committee that were posted online last week.

“The FBI is investigating a cyber intrusion involving the DNC and are working to determine the nature and scope of the matter,” read a statement from the FBI. “A compromise of this nature is something we take very seriously, and the FBI will continue to investigate and hold accountable those who pose a threat in cyberspace.”

The release of nearly 20,000 emails from top DNC aides include at least a year and four months of communications from top officials such as chairwoman Debbie Wasserman Schultz.

The cyber-intrusion has been attributed to Russian hackers.

Wasserman Schultz announced that she would step down after the convention.