Months before news of a July 25 phone call between President Donald Trump and Ukrainian President Volodymyr Zelensky pushed the decision to launch an impeachment inquiry, Trump had called the newly elected leader to pressure him to work with personal attorney Rudy Giuliani on investigations, according to a New York Times report published Wednesday.

Within hours of Zelensky winning Ukraine’s election on April 21, Trump called him to coordinate with Giuliani and investigate what he said was “corruption,” people familiar with the call told the Times.

The calls highlighted what the Times said was Trump’s years-long obsession with Ukraine, fueled initially by what he saw as the country’s role in former special counsel Robert Mueller’s investigation into Russian influence in the 2016 presidential campaign and later by using the Ukrainian government to help take down Joe Biden, the former vice president and a potential Democratic 2020 rival.

Zelensky’s aides came to understand Trump’s calls for fighting “corruption” as a euphemism for the Biden family and for Ukrainians who in 2016 released jeopardizing information about the Trump campaign, the newspaper reported.

In the July 25 call, Trump asked Zelensky to “do us a favor” right after the Ukrainian leader said he was thankful for the U.S. military aid to the country, according to a summary of the call provided by the White House. That call came as the U.S. had frozen nearly $400 million in military aid to Ukraine.

The first part of that favor was for Zelensky to investigate a conspiracy theory that the Democratic National Committee servers hacked by Russia to benefit Trump’s campaign in 2016 were not actually hacked. He also, like in the April call, pressured Zelensky to meet with Giuliani and speak with Attorney General William Barr to find dirt on Biden and his son Hunter Biden.

Sen. Chris Murphy (D-Conn.) said earlier this week that Zelensky’s administration was concerned that the U.S. was cutting off aid “for their unwillingness, at the time, to investigate the Bidens,” citing his communication with Ukrainian officials, including Zelensky, when the senator visited the country this month, The Washington Post reported Monday.

Trump said earlier this week that he had blocked the military aid because of concerns about corruption in Ukraine. But a Defense Department letter from May obtained by NPR said that Ukraine had taken “substantial actions” to fight corruption and was subsequently cleared to receive the military aid, which had been blocked until Sept. 11.

Giuliani’s shadow diplomacy in Ukraine while Trump’s personal attorney has frustrated some State Department officials who didn’t know about his work there, the Post reported Tuesday.

Giuliani has been working for months with current and former Ukrainian prosecutors to push for investigations he admitted would politically benefit Trump, the Times reported in a May interview.

The July 25 call was mentioned in a whistleblower complaint that came from inside the intelligence community, and the disclosure helped prompt Tuesday’s announcement of a formal impeachment inquiry into Trump.