The disclosure came as the FBI released its second batch of documents from its investigation into Clintons private email server during her tenure as secretary of state. The 189 pages the bureau released includes interviews with some of Clintons closest aides, such as Huma Abedin and Cheryl Mills; senior State Department officials; and even Marcel Lazar, better known as the Romanian hacker Guccifer.
In an April 5, 2016 interview with the FBI, Abedin was shown an email exchange between Clinton and Obama, but the longtime Clinton aide did not recognize the name of the sender.
Once informed that the senders name is believed to be a pseudonym used by the president, Abedin exclaimed: How is this not classified? the report says. Abedin then expressed her amazement at the presidents use of a pseudonym and asked if she could have a copy of the email.