House Oversight Committee Chair James Comer (R-KY) and Judiciary Committee Chair Jim Jordan (R-OH) wrote a demand letter to White House Counsel Edward Siskel to investigate whether President Joe Biden engaged “in a conspiracy to obstruct a proceeding of Congress” with Hunter Biden, Breitbart News learned Wednesday.

Hunter defied a congressional subpoena to testify behind closed doors during a December 13 press conference.

White House Press Secretary Karine Jean-Pierre said Joe Biden was “certainly familiar with what his son was going to say” at the press conference.

Jean-Pierre refused to provide any more information on the subject.

“In light of an official statement from the White House that President Biden was aware in advance that his son, Hunter Biden, would knowingly defy two congressional subpoenas,” the lawmakers wrote, “we are compelled to examine as part of our impeachment inquiry whether the President engaged in a conspiracy to obstruct a proceeding of Congress.”