Miles Taylor, the former chief of staff at the Department of Homeland Security, revealed on Wednesday afternoon that he’s the Trump administration official who anonymously penned a New York Times opinion piece and a subsequent book painting the president as inept and unfit for office. “Too often in times of crisis, I saw Donald Trump prove he is a man without character, and his personal defects have resulted in leadership failures so significant that they can be measured in lost American lives,” he wrote in a Medium post. “I witnessed Trump’s inability to do his job over the course of two-and-a-half years. Everyone saw it, though most were hesitant to speak up for fear of reprisals.” Taylor, who resigned from DHS in June 2019, said he penned A Warning as “a caution to voters that it wasn’t as bad as it looked inside the Trump Administration—it was worse.”

The former DHS aide served under Kirstjen Nielsen while families were being separated at the southern U.S. border. Taylor was hired by Google last year, a move some members of the U.S. House of Representatives slammed in a letter to the company, accusing him of overseeing “the implementation” of the Trump administration’s ban on visitors from six Muslim-majority nations. Trump tore into Taylor at an Arizona rally on Wednesday, calling him a “sleaze bag” who “should be prosecuted.”