Lev Parnas, an associate of Rudy Giuliani, told a federal judge Wednesday he will not testify during his own trial on charges that he used a Russian financier’s money to contribute funds to U.S. political candidates.

Parnas, a businessman who once identified himself as someone who could expose corruption in former President Donald Trump’s administration over its dealings in Ukraine, announced his refusal to testify one day after prosecutors concluded an evidence presentation against him. He and his co-defendant, Andrey Kukushkin, have pleaded not guilty to all charges.