Impeachment inquiry: Key witnesses quizzed about Trump and Ukraine - BBC News
Lt Col Vindman listened to the phone call that sparked the impeachment inquiry against the US president.
As we wait for the afternoon session to start, let's take a look at a central figure in this saga.

On the now infamous 25 July call, Trump asked Ukraine’s leader to co-ordinate with his personal lawyer Giuliani on any inquiry into the Bidens.

The former New York City mayor has already admitted to pushing Ukrainian officials to investigate unsubstantiated corruption allegations against Joe Biden.

He was to travel to Ukraine in May, but eventually decided against it. Earlier this year, two of his associates who helped connect Giuliani with Ukrainian officials were arrested on unrelated campaign finance charges.

Giuliani has also been accused of trying to discredit former Ukraine ambassador Marie Yovanovitch, who gave compelling testimony on Friday, while running his shadow foreign policy in Ukraine.

He has been subpoenaed for documents by impeachment investigators, though he’s previously said he won’t co-operate with Democrats.