WASHINGTON — Acting U.S. Ambassador to Ukraine Bill Taylor left Kyiv, Ukraine on Wednesday for Washington D.C. after House Democrats requested he appear for a Tuesday deposition in the investigation into President Trump’s alleged misconduct involving Ukraine, NBC News has confirmed.

Taylor is a crucial eye witness to Trump’s attempts to press Ukainian President for an investigation of Joe Biden’s son Hunter, who sat on the board of Ukrainian energy company, Burisma.

His return to the U.S. and deposition comes as numerous Trump officials, including acting European Union ambassador Gordon Sondland, are defying the White House’s attempts to bloc testimony from Congress and providing critical testimony to Congress.

In a packet of text messages released by House Democrats last week, Taylor on Sept. 9 remarked that it would be “crazy” to link Ukraine military assistance to help with Trump’s political campaign, something that was hinted at in the messages. "I think it’s crazy to withhold security assistance for help with a political campaign," Taylor said in a text.

Nearly five hours later, Sondland — a Republican donor who has no experience in diplomacy or foreign policy, responded after speaking with the president, writing, "Bill, I believe you are incorrect about President Trump’s intentions. The President has been crystal clear no quid pro quo's of any kind.”