Yuriy Lutsenko, Ukraine's former prosecutor general, told the Los Angeles Times that President Donald Trump's personal lawyer, Rudy Giuliani, was "obsessed" with potential misconduct on the part of former Vice President Joe Biden or his son, Hunter.

Lutsenko said he repeatedly pushed back on Giuliani's requests to investigate the Bidens.

Lutsenko and Giuliani met in person twice this year, he told the LA Times, in addition to "numerous" phone conversations.

Lutsenko's comments are linked to broader concerns tied to a July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky — a conversation at the heart of a whistleblower complaint that sparked an impeachment inquiry.

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Ukraine's former top prosecutor, Yuriy Lutsenko, said he repeatedly pushed back on requests from President Donald Trump's personal lawyer, Rudy Giuliani, to investigate former Vice President Joe Biden and his son, Hunter.

Biden is a top contender for the 2020 Democratic presidential nomination.

In an interview with the Los Angeles Times, Lutsenko on Sunday described Giuliani as being "obsessed" with potential misconduct on the part of the Bidens. Lutsenko and Giuliani met in person twice this year, he told the LA Times, and they had "numerous" phone conversations.

Lutsenko, who was fired as Ukraine's prosecutor general last month, told the LA Times that he informed Giuliani he had no evidence of wrongdoing on the part of the Bidens and had no knowledge either had done anything illegal.

He told Giuliani he would cooperate with any US investigations related to the Bidens but made clear he did not want Ukraine to be used in what the LA Times referred to as a "political vendetta" that could impact the 2020 US election.

"I said, 'Let's put this through prosecutors, not through presidents,'" Lutsenko told the Times. "I told him I could not start an investigation just for the interests of an American official."

Read more: Trump's actions with Ukraine were 'profoundly stupid' and beyond anything any president has ever done, historians and veteran diplomats say

There's no evidence the Bidens were involved in illegal activity in Ukraine

Lutsenko's comments are linked to broader concerns tied to a July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky. The phone call and Giuliani's efforts are also at the center of a whistleblower complaint from a US intelligence official that sparked a formal House of Representatives impeachment inquiry into the president.

The official who filed the complaint alleged that Trump solicited foreign interference from Ukraine in the 2020 election. They said they were "deeply concerned" Trump's actions met the definition of an "urgent" concern under federal law. The intelligence community inspector general, Michael Atkinson, backed up that view.

The complaint mentioned Giuliani 31 times and described him as a "central figure" in the president's efforts to investigate the then-Democratic presidential frontrunner. It said Attorney General William Barr "appears to be involved as well." A memo of the call released by the White House confirms much of what was in the complaint, and quotes Trump urging Zelensky to work with Giuliani and Barr to investigate the Bidens.

Read more: Republican support for impeaching Trump doubled in the past few days amid escalating Ukraine scandal

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the Attorney General would be great," Trump said, according to the memo. "Biden went around bragging that he stopped the prosecution so if you can look into it...It sounds horrible to me."

At the heart of Trump's allegations are Hunter's ties to a Ukrainian natural gas company, Burisma Holdings, and the former vice president's role in calling for the ouster of Ukraine's former prosecutor general, Viktor Shokin.

Shokin was pushed out in March 2016, when Biden was the Obama administration's point person on Ukraine. He said he wanted Shokin fired because of the prosecutor's poor record on fighting corruption. Biden represented the US's official position on the matter, one that was shared by many other Western governments and anticorruption activists in Ukraine, according to The Associated Press.

However, Trump and Giuliani allege that Biden pushed for Shokin's ouster because he wanted to stymie the investigation into Burisma.

But government officials and Ukrainian anticorruption advocates counter that Shokin had hampered the investigation into Burisma long before Biden even stepped into the picture, according to The Wall Street Journal.

In other words, the available evidence suggests Biden was doing the opposite of what Trump and Giuliani are implying: He was trying to oust a prosecutor who was slow-walking corruption investigations. Moreover, the investigation into Burisma was largely dormant by the time Shokin was dismissed.

Zelensky and Trump met on the sidelines of the United Nations General Assembly in New York City last week, where Zelensky said he did not want to be involved in US elections but also that he did not feel "pushed" by Trump in what the Ukrainian leader described as a "normal call."

Trump pointed to Zelensky's comments as backing up his defense that nothing untoward took place during their July phone call.

Read more: 'This was his show': Rudy Giuliani emerges as the key to unraveling the Trump-Ukraine whistleblower scandal

Lutsenko is a key player in the escalating Trump-Ukraine scandal

According to the LA Times, Lutsenko told Giuliani that Hunter's role at Burisma as his father was heavily involved in US policy "could be signs of a conflict of interest" but was not illegal.

Lutsenko's comments on this topic are somewhat mixed, and some reporting has pointed to him as someone who stirred up questions about the Bidens and Burisma earlier this year. In April, he told a conservative columnist at The Hill he would be "happy" to talk to Barr about the matter.

Lutsenko was Ukraine's prosecutor general from May 2016 to August 2019 under President Petro Poroshenko, who lost by a landslide to Zelensky in Ukraine's presidential election in late April.

Less than a month later, in an interview with Bloomberg in May, Lutsenko again addressed the allegations from Giuliani against the Bidens. By that point, the former vice president had officially hopped in the 2020 race.

Lutsenko said, "I do not want Ukraine to again be the subject of US presidential elections," adding, "Hunter Biden did not violate any Ukrainian laws — at least as of now, we do not see any wrongdoing. A company can pay however much it wants to its board." Hunter reportedly made around $50,000 a month, or $600,000 a year, as he served on Burisma's board from April 2014 until early this year.

Addressing the topic once again in an interview with The Washington Post last week, Lutsenko said, "From the perspective of Ukrainian legislation, [Hunter Biden] did not violate anything.