MOSCOW (Sputnik) — The information was revealed in a batch of emails of Clinton's campaign chairman John Podesta published by the whistleblowing website.
An email with de Blasio's tweet saying "I’ve always liked what i heard from Bernie Sanders [on income inequality]" was sent out by Battleground state communications person Ian Sams on June 10, 2015 to other Clinton's campaign members, including Podesta. Mook replied to the email sending a message, "Wow. What a terrorist."
De Blasio endorsed Clinton in late October 2015.
WikiLeaks published the first batch of Podesta's emails on October 8.