Texts show US diplomat pushing Ukraine on probe for Trump meeting Messages, released by the House Democrats, show former US special envoy to Ukraine Kurt Volker writing to top Zelensky aide Andrey Yermak, promising the new Ukrainian leader a trip to Washington in exchange for the investigation. "Heard from White House -- assuming President Z convinces trump he will investigate / 'get to the bottom of what happened' in 2016, we will nail down date for visit to Washington. Good luck!" Volker wrote in the July 25 message. IMAGES