In a post on Truth Social overnight, President Donald Trump claims that some pardons by President Joe Biden are “VOID, VACANT, AND OF NO FURTHER FORCE OR EFFECT,” saying an autopen was used to forge the former president’s signature.

Trump alluded specifically to Biden’s pardons for members of the House January 6th Committee, claiming that the pardon signatures had been “done by Autopen” and that Biden “knew nothing about them.” He added that “the people that did may have committed a crime.” However, the president offered no evidence that Biden was unaware of the pardon or that an autopen — a robotic device that mechanically copies a signature — had been used.

Trump’s post echoes claims made last week by the conservative Heritage Foundation, which alleged that Biden’s signature on several pardons was identical, implying the use of an autopen. The New York Post further claimed that a Biden aide “made unilateral determinations” to sign documents using an autopen. The idea that Biden was unaware of these pardons, however, is contradicted by his public statements about them. In a January 20th statement on pardoning January 6th Committee staff and others, Biden said that although he felt that the recipients would “ultimately be exonerated,” investigations of them could “irreparably damage” their reputations and finances.

In the years since losing the 2020 election to Biden, Trump has vowed political revenge multiple times. Before the Supreme Court issued its decision on presidential immunity, he told Time that depending on that decision, “Biden, I am sure, will be prosecuted for all of his crimes.” As an NPR story last year describes, Trump has said similar things about Vice President Kamala Harris, as well as Liz Cheney, who served as the vice chair of the House Select Committee on the January 6 Attack. His new Truth Social post, similarly, claims “those on the Unselect Committee” are “subject to investigation at the highest level.”

Presidents and other politicians have long used autopens to sign documents, with President Gerald Ford having been among the first to admit to its use. President Barack Obama signed a bill remotely with an autopen in 2011, pointing to a Bush White House legal team memo that said the president could sign something “by directing another to affix one’s name or seal to the document in one’s presence.” As Bloomberg notes, the Justice Department also held in 1929 that “neither the Constitution nor statute prescribed the method by which executive clemency shall be exercised or evidenced. It is wholly for the president to decide.”