President Trump asked Ukraine’s president to investigate Hunter Biden, son of 2020 Democratic candidate Joe Biden, eight separate times during one phone call this summer, the Wall Street Journal reported Friday.

According to the Journal’s sources, Trump told President Volodymyr Zelensky in that July phone call to work with the president’s lawyer Rudy Giuliani on probing the former vice president over allegations he shielded from investigation a Ukrainian gas company with ties to his son.

“Mr. Trump didn’t mention a provision of foreign aid to Ukraine on the call, said this person, who didn’t believe Mr. Trump offered the Ukrainian president any quid-pro-quo for his cooperation on an investigation,” the Journal added.

Trump’s interactions with the Ukrainian president have come under scrutiny following news of a whistleblower’s complaint about the president’s communications with a foreign leader and a “promise” Trump allegedly made in those conversations.