https://www.npr.org/2019/10/11/769049841/fired-u-s-ukraine-ambassador-arrives-on-capitol-hill-to-testify-in-impeachment-p
The career diplomat was recalled from her post in May after criticism from some Republicans, including Donald Trump Jr., the president's eldest son, that she was not supportive of the administration's policies. She was appointed by former President Obama in 2016 and confirmed without any controversy by the GOP-led Senate.