"Given the sensitive nature of the request, I appreciate your keeping that information closely held to those who need to know to execute direction," Duffey said.
While a formal notification would be sent later that day, this was the first clear sign that the aid was being held -- a short time after the phone call in which Trump pressed Zelensky for investigations that could boost Trump politically.
Senate Minority Leader Chuck Schumer renewed his call for Duffey to be a witness at the Senate impeachment trial, saying that email showcases the information he may be able to offer.
"This email from Michael Duffey -- approximately 90 minutes after President Trump's call with the president of Ukraine -- is all the more reason why we need Duffey and others to testify in a Senate trial," the New York Democrat tweeted Saturday. The budget office dismissed linking the hold of the aid to the call, noting it was announced at a mid-July interagency meeting.
"It's reckless to tie the hold of funds to the phone call. As has been established and publicly reported, the hold was announced in an interagency meeting on July 18. To pull a line out of one email and fail to address the context is misleading and inaccurate," Rachel Semmel, a spokeswoman for the OMB, said in a statement to CNN.
While an OMB official notified other agencies of the freeze on July 18, it is notable that the first official action to withhold Pentagon aid came the same day as Trump's call with Zelensky
The call between Trump and Zelensky went from 9:03 am to 9:33 am and then the email from OMB's Duffey is time stamped at 11:04 am. That same email also appears elsewhere in the same batch released Friday with a 3:03 pm time stamp.
A judge ordered the Office of Management and Budget and the Pentagon to hand the documents over to the Center for Public Integrity Friday in response to a FOIA request. The Center for Public Integrity published the documents
late Friday night.
While much of the release was redacted, the documents shed some light on the conversations between two government organizations who were carrying out the President's orders even amid concerns by some that they could run afoul of the law.
One of the earliest signs of President Trump's concerns about the funds stems from a June 19 article in the Washington Examiner
discussing the congressionally approved military aid for Ukraine totaling $250 million.
The President apparently took note of the article and Duffey asked the Pentagon's chief financial officer about the plan to support Ukraine the same day the article was published.
"The President has asked about this funding release, and I have been tasked to follow-up with someone over there to get more detail."
Trump would go on to freeze the funds and, as the freeze dragged on, officials began raising concerns about the possibility of getting the money to Ukraine in time -- even if the hold was lifted.
On September 5, Department of Defense Comptroller Elaine McCusker
mentioned the "increasing risk of execution," a nod to concerns at the Pentagon that continuing hold could prevent all the money from being spent.
Finally, on the evening of September 11, Duffey alerted McCusker that he is releasing the money for Ukraine.
"Copy. What happened?" McCusker asks.
The first line of Duffey's response is redacted. He goes on to say he hopes to sign the apportionment to release the money that evening and signs off, "Glad to have this behind us."
Also on Friday night, the government transparency group American Oversight received five pages of heavily redacted emails about the Ukraine aid, including some sent by Department of Defense Secretary Mark Esper.
The document releases Friday come in response to FOIA lawsuits, which members of the public and third-party groups often use to gain access to documents the executive branch has not released otherwise.
Though these releases have been heavily redacted, they begin to shade in more detail about officials' exchanges regarding the Ukraine aid pause, which House Democrats pursued as they investigated and impeached the President but could not access because of the White House's refusal to comply with congressional subpoenas.
More public document releases are scheduled in January to groups that have sued.