A new report on Ukraine features a former adviser to President Volodymyr Zelensky saying that discussing the Bidens was understood as a condition of a call between Zelensky and President Donald Trump.

Serhiy Leshchenko, a former member of the Ukrainian parliament, told ABC News that after Zelensky’s election, they wanted to speak with the U.S. president:

But after weeks of discussions with American officials, Ukrainian officials came to recognize a precondition to any executive correspondence, the adviser said.

“It was clear that [President Donald] Trump will only have communications if they will discuss the Biden case,” said Serhiy Leshchenko, an anti-corruption advocate and former member of Ukraine’s Parliament, who now acts as an adviser to Zelenskiy. “This issue was raised many times. I know that Ukrainian officials understood.”

Leshchenko also talked about Rudy Giuliani‘s push for a Biden investigation and said he believes then-prosecutor general Yuri Lutsenko “invented the investigations that Giuliani pushed as part of an effort to keep his job.”