The US State Department will do everything necessary to determine whether former US ambassador Marie Yovanovitch was under threat in Ukraine, Secretary of State Mike Pompeo said on Friday.
Documents released this week indicated Lev Parnas, a Ukraine-born US citizen, helped US President Donald Trump's personal lawyer Rudy Giuliani investigate US presidential candidate Joe Biden and his son Hunter.
They also showed Parnas was involved in monitoring Yovanovitch's movements before Trump removed her in May. Yovanovitch, a respected career diplomat, was a key witness in the U.S. House of Representatives' investigation of Trump before he was impeached in December.
Late on Friday, a Democratic aide said House Democrats will be sending additional text messages, photographs and other documents provided by Parnas for the Senate impeachment trial that gets underway in earnest next week.