More bombshell Vindman testimony: Ukraine aid was 'contingent' on Biden probe

NBC News' Geoff Bennett and Leigh Ann Caldwell are reporting that Lt. Col. Alexander Vindman told congressional investigators this week that the White House made legislatively appropriated aid to Ukraine "contingent" upon launching probes of former Vice President Joe Biden.

If Bennett and Caldwell's reporting is accurate, it would make Vindman the second witness to publicly testify that aid to Ukraine was being held up until the country agreed to launch investigations into the President Donald Trump's political opponents.

Last week, ambassador Bill Taylor testified that European Union ambassador Gordon Sondland said that both the military aid to the country and a face-to-face meeting between Trump and Ukrainian President Volodymyr Zelensky would only occur if Ukraine agreed to investigate both Biden and the Crowd Strike server conspiracy theory that relates to the hacking of the Democratic National Committee in 2016.

Trump so far has denied that there was any quid-pro-quo when it came to delivering Ukraine aid, but now it appears two witnesses with direct knowledge of the situation are contradicting that.