Ukrainian President Volodymyr Zelensky is taking his anti-corruption, pro-reform agenda seriously, with plans to boot more than 500 Ukrainian prosecutors from the governmental payroll by the end of the month.

And some of those prosecutors are directly tied to to President Trump attorney Rudy Giuliani and his pressure campaign to get Ukraine to probe the Biden family, one of Trump’s top 2020 political rivals. According to the Washington Post, a prosecutor named Kostiantyn Kulyk will be among the officials pushed out this month. Kulyk is one of the key Ukrainian officials who aided Giuliani is his effort to churn out fabricated dirt on the Bidens. The prosecutor has denied he ever met with Giuliani, but his ex-associates say he wrote a seven-page memo that Kulyk’s boss later handed off to Giuliani, according to the Post.

Kulyk was fired because he did not provide officials with proof that he took an exam that’s now part of the prosecutor review process across the country.

According to the Post, Zelensky’s efforts to root out corruption in his own country may harm his relationship with Trump, who’s currently under impeachment inquiry in the House for an alleged effort to recruit Zelensky to probe his political rival.