In his eye-popping press conference last week, White House Acting Chief of Staff Mick Mulvaney said that the Trump administration withheld military aide from Ukraine in part to secure cooperation with a Justice Department investigation into the origins of Robert Mueller’s Russia probe. But a former top U.S. envoy to Ukraine has said the DOJ never actually asked the White House for that help.

Mulvaney has since tried to walk back his claim, saying the administration only held up military aid to Ukraine because of the country’s corruption and because other countries weren’t giving more aid as well. But the fact that his initial version of events differed so far from the testimony of another main player in the Ukraine saga highlights the White House’s struggle to defend itself.

During his congressional deposition earlier this month, former U.S. Special Representative for Ukraine Kurt Volker said that the Trump administration’s Department of Justice never officially asked Ukrainian law enforcement for help probing 2016 election interference or the company where Hunter Biden was a board member, according to sources familiar with what Volker said. Trump himself asked Ukraine’s president to scrutinize that company, Burisma, according to a memorandum of their conversation. But Volker has said that to his knowledge the Justice Department never officially made its own ask.

A DOJ spokesperson and a lawyer for Volker both declined to comment for this story.

Volker said the topics of Burisma and election interference came up as he, Rudy Giuliani, and European Union Amb. Gordon Sondland worked with a top aide to Ukrainian President Volodymyr Zelensky on a statement about U.S.-Ukraine relations. Zelensky wanted to meet with President Donald Trump at the White House after having recently been inaugurated, and Volker and Sondland also wanted Trump and Zelensky to meet. But Giuliani––Trump’s personal lawyer and close outside advisor––said the Ukrainians should first release a public statement on corruption. And he wanted it to mention two things: alleged Ukraine meddling in the 2016 election and Burisma.

The Zelensky aide, Andrey Yermak, wanted to know if the U.S. Justice Department had officially asked Ukraine for help on those two matters. Volker told Congress that he reached out to Bruce Swartz, a senior DOJ official who deals with international issues, but that he didn’t hear back. He said that he was later told that DOJ made no such official request.

The Ukrainians and Volker ultimately agreed that it was best not to release a statement, in part because the DOJ hadn’t officially asked them for help on 2016 interference or Burisma. Volker has said that, at the time, he was not aware that Trump had directly asked Zelensky about the Bidens.

The narrative of events appears to counter Mulvaney’s Thursday press conference, during which the acting chief of staff said that the administration temporarily withheld military aid from the Ukrainians for three reasons.

“Three issues for that,” he said. “The corruption in the country, whether or not other countries were participating in the support of the Ukraine, and whether or not they were cooperating in an ongoing investigation with our Department of Justice. That’s completely legitimate.”

The Justice Department pushed back against Mulvaney’s comments shortly after his press conference on Thursday. “If the White House was withholding aid in regards to the cooperation of any investigation at the Department of Justice, that’s news to us,” one senior DOJ official told reporters.

And on Sunday, Mulvaney insisted he never actually said there were three issues for holding up aid. “Again, that’s not what I said, that's what people said I said,” Mulvaney said. “ Here’s what I said… there were two reasons that we held up the aid.”

Volker’s testimony is consistent with the DOJ statement, and goes further––indicating that, as far as one of America’s top envoys to Ukraine knew, the Justice Department under the Trump administration never officially asked the Ukrainians for help probing Burisma and 2016 election interference.

But while DOJ may not have made the ask, the president himself certainly did. On their July 25 phone call, Trump pushed Zelensky to talk with Giuliani about the removal of a Ukrainian prosecutor who had scrutinized Burisma.

“I will ask him [Giuliani] to call you along with the Attorney General,” Trump told Zelensky, according to the White House’s memo on their call.

“I will have Mr. Giuliani give you a call and I am also going to have Attorney General Barr call and we will get to the bottom of it,” Trump added.

Volker has maintained that he did not know Trump offered to have Barr and Giuliani call Zelensky until the public knew. If Volker’s understanding of the issue is accurate, then the DOJ did not officially follow up with Ukraine’s Ministry of Justice regarding Burisma and 2016. According to The Wall Street Journal, the DOJ has said Trump didn’t ask Barr to reach out to Kyiv––despite telling Zelensky he would do so.