Michael Cohen, Donald Trump’s scorned ex-confidant, testified against his former boss during an electric day in court, telling a New York judge that Trump commanded him to “reverse engineer” estimates of the former president’s financial wealth.

The appearance Tuesday by Cohen, which came in the New York attorney general’s civil-fraud against the former president and his business, placed the two men face-to-face five years after their bitter split. When Cohen took the stand midday in the Manhattan courtroom and swore to tell the truth, Trump sat nearby at the defense table—cross-armed and stone-faced.