President Donald Trump declared his predecessor’s pardons for members of the House select committee that investigated the Jan. 6, 2021 attacks on the Capitol to be invalid early Monday, because President Joe Biden didn’t use a real pen.

“The ‘Pardons’ that Sleepy Joe Biden gave to the Unselect Committee of Political Thugs, and many others, are hereby declared VOID, VACANT, AND OF NO FURTHER FORCE OR EFFECT, because of the fact that they were done by Autopen,” Trump wrote on his Truth Social online platform.

Trump went on to allege that Biden didn’t know about the pardons or approve them, and said that therefore all the committee members would be “subject to investigation at the highest level.”

It wasn’t clear if the president was planning imminent action or an investigation against the committee members. The White House was contacted for comment.

Biden ordered the pre-emptive pardons in January this year in one of his final acts in office. Biden said he took the action to ensure that public figures who had investigated and criticized Trump while in office would not face retaliatory action under his new administration.

Trump has argued that the committee members are guilty of unspecified “major crimes,” writing the phrase in all capital letters in a text message to NBC News after Biden issued the pardons in January.

The panel’s members were Sen. Adam Schiff, D-Calif., who was then a House member; former Reps. Liz Cheney, R-Wyo., Adam Kinzinger, R-Ill., Elaine Luria, D-Va., and Stephanie Murphy, D-Fla.; and current Reps. Pete Aguilar, D-Calif., Zoe Lofgren, D-Calif., Jamie Raskin, D-Md., and Bennie Thompson, D-Miss.

Former Joint Chiefs of Staff Chairman Mark Milley and Dr. Anthony Fauci also received pre-emptive pardons from Biden.

Biden was a prolific issuer of pardons in his final days in office and set a new record for presidential clemency with almost 2,500 sentences commuted, including more than 2,000 people convicted of nonviolent drug offenses.

Trump himself also pardoned some 1,500 criminal defendants charged in the Jan. 6 Capitol attack and commuted the sentences of 14 of his supporters, including members of the Proud Boys and Oath Keepers groups, who were convicted of seditious conspiracy.