Marie Yovanovitch, the former American ambassador to Ukraine, appeared before the House Intelligence Committee on Friday for the second public hearing of the inquiry to impeach US President Donald Trump. In a closed-door testimony in October, Ms Yovanovitch had said she “felt threatened” by Mr Trump during his call with the president of the Ukraine, which led to the opening of the inquiry. Democrats began the impeachment proceedings against Mr Trump in September, after a whistle blower complained that he abused power in a phone call with Volodymyr Zelenskiy, the Ukrainian president. The revelations indicated that Mr Trump attempted to pressure his Ukrainian counterpart to investigate Hunter Biden, the son of his main Democratic rival in the 2020 presidential election Joe Biden. In front of the committee on Friday, Ms Yovanovitch stressed the power of disinformation, saying that much of the criticism against her, including that by Mr Trump’s lawyer Rudy Guiliani and Ukraine’s then-top prosecutor Yuri Lutsenko, was not true. The two men had accused her of being part of a conspiracy involving anti-corruption probes in Ukraine and efforts by the Trump administration to investigate ties between Ukrainian officials and Mr Trump’s 2016 election rival Hilary Clinton. In May, after complaints from Mr Giuliani and other Trump allies that Ms Yovanovitch was undermining and obstructing Mr Trump's efforts to persuade Ukraine to investigate Joe Biden, the previous vice-president, she was fired. Her dismissal, which shocked officials across the diplomatic community, is central to the impeachment inquiry. Ms Yovanovitch is the third witness to publicly testify in the Democratic impeachment effort to oust Mr Trump. The hearings in Washington will determine whether there is enough evidence to prepare charges against the US president. Ms Yovanovitch’s appearance came as the White House on Friday released the first call between Mr Trump and Mr Zelenskiy, made three months before the call that sparked the impeachment proceedings. Republican Devin Nunes, during his opening remarks on Friday, read the newly released transcript of Mr Trump’s April phone call with Mr Zelenskiy where he was congratulated on becoming Ukrainian president. In the remarks, Mr Zelenskiy called Mr Trump a “great example” and invited him to attend the inauguration. Mr Trump responded that at the least, a “great representative” would attend. The released transcripted, which may have been vetted, didn't Mr Trump mentioned either Joe Biden or his son on the call. Mr Nunes also said the witnesses being brought before the impeachment hearings are giving second-hand accounts. “In other words, rumour,” he said. “I’ll note that House Democrats vowed they would not put the American people through a wrenching impeachment process without bipartisan support — and they have none,” Mr Nunes said. “Add that to their ever-growing list of broken promises and destructive deceptions.” Mr Trump fired out a couple of tweets on Friday, attacking Nancy Pelosi, who is leading the impeachment inquiry against the president. He also attacked Ms Yovanovitch, saying that "everywhere she went turned bad." The president, who regularly watches live television, will likely be tuned into the inquiry. Meanwhile Roger Stone, a longtime friend of Mr Trump, was found guilty on Friday of witness tampering and lying to Congress about his pursuit of Russian-hacked emails damaging to Hillary Clinton’s 2016 election bid. He becomes the sixth aide or adviser of Mr Trump to be convicted as part of special counsel Robert Mueller’s Russia investigation. Stone denied the seven charges but now faces up to 20 years in prison.