National Security Council analyst Alexander Vindman told impeachment investigators the transcript of the July call between Donald Trump and President Zelensky of Ukraine omitted, according to the New York Times, “crucial words and phrases, and that his attempts to restore them failed, according to three people familiar with the testimony.“

The Army Lt. Colonel said the omissions included assertions by Trump that there were recordings of Joe Biden discussing corruption in Ukraine and an “explicit mention” by Ukrainian President Zelensky of Burisma Holdings, the company whose board of directors employed Hunter Biden, the former Vice President’s son.

The Times also writes:

“Colonel Vindman did not testify to a motive behind the editing process. But his testimony is likely to drive investigators to ask further questions about how officials handled the call, including changes to the transcript and the decision to put it into the White House’s most classified computer system — and whether those moves were meant to conceal the call’s most controversial aspects.”

The Times also reports it’s not clear why Colonel Vindman’s changes to the transcript weren’t made.