Dick Costolo said his job was safe a month ago by Laura Lorenzetti @FortuneMagazine June 11, 2015, 5:51 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Twitter CEO Dick Costolo announced Thursday afternoon that he will be stepping down as of July 1, handing the reins over to cofounder Jack Dorsey, who will serve as interim CEO. That’s a drastic turn of events given his comments at the Re/Code Code Conference just a month ago. Costolo, who has led the social media company since October 2010 after taking over for Evan Williams, was asked point blank by host Kara Swisher if he expected to have his job by January given the tumultuous year Twitter’s had so far. Indeed, many analysts and investors have been speculating if it was time for a leadership change. But Costolo blew off the concerns, Business Insider reports: The board and I are totally in sync about what we need to do — we have a very clear strategy that we’ve articulated and that we’re following. I don’t worry about whether I’ll be there at the end of the year. Twitter Inc. – Stock Price and Volume | FindTheCompany Costolo said that if anything, he’s an over-communicator, making sure the Twitter TWTR board is always aligned on strategy and expectations. It seems like that alignment shifted course in recent weeks, leaving Costolo behind.