Trump made the remark about the probe into his into his abuse of power regarding withholding Ukrainian military aid. He also claimed that the probe was “without due process or fairness or any legal rights,” despite the House’s use of investigative and impeachment powers as outlined in the Constitution. One would assume that the single chamber of Congress would not be able or allowed to conduct an ostensibly illegal investigation into the President. The probe was to investigate Trump’s call to the President of Ukraine where he asked for damaging information on Joe Biden in exchange for military aid that had already been granted by Congress.

Politico – Trump provokes outrage by calling impeachment inquiry ‘a lynching’
NPR – Trump Calls Impeachment Inquiry A ‘Lynching’