Democrats on Thursday moved ahead with a confirmation hearing of Alejandro Mayorkas to the No. 2 position in the Department of Homeland Security despite a Republican boycott of the meeting and an ongoing investigation into President Obama’s appointee.

Mayorkas, a top immigration official, unequivocally denied any wrongdoing in the face of reports that he helped a technology company secure U.S. visas for Chinese nationals. Democrats, too, sought to stomp out allegations that Mayorkas ran afoul of the law as they look to fill the department’s 15 vacancies in senior positions, including the top two posts.