President Obama used a pseudonym when sending or receiving emails through the private server system Hillary Clinton used as secretary of state, according to nearly 200 pages of documents released Friday by the FBI.

Included in the documents are notes from an April 2016 interview with long-time Clinton aide Huma Abedin, conducted in connection with the FBI’s two-year investigation into Clinton’s use of the private server for official correspondence.

One note was about the FBI showing Abedin an email address “believed to be a pseudonym used by the President,” as reported by Politico and other news-gathering agencies.

Abedin said she didn’t recognize the name and “expressed her amazement” that Obama apparently used a pseudonym.

She also exclaimed, “How is this not classified?” according to the documents.

That email exchange occurred on June 28, 2012, with the subject line “Congratulations,” perhaps regarding a Supreme Court ruling on ObamaCare. However, federal lawyers will not release the emails, citing executive privilege.

The FBI concluded its investigation this summer, finding that several Clinton emails included at least parts of classified information and that the now-Democratic presidential nominee was “extremely careless.”

However, the agency did not recommend criminal charges, and the investigation was concluded.

Abedin also reportedly told the FBI that Clinton’s team had to inform the White House that Clinton was changing her email address so that Obama could receive her messages.