Manhattan prosecutors may have found their “insider” as a grand jury considers whether charges are warranted against former President Donald Trump, according to a top prosecutor in Robert Mueller’s special counsel investigation.

Andrew Weissmann, a former Justice Department official and FBI general counsel, said reports about the testimony of a senior Trump Organization official may be a game-changer for the New York-based inquiry. Trump denies any wrongdoing and in February decried what he dubbed a “new phenomenon of ‘headhunting’ prosecutors and AGs.”