Rep. James Comer, R-Ky., has been leading the probe into Joe Biden’s cognitive state during his presidency, with Republicans alleging that Biden's occasional use of an “autopen” to sign documents — a practice other presidents have done as well — demonstrated that he wasn’t fully in control or aware of what his administration was doing.

But documents show that some of the letters and subpoena notices Comer has sent out in connection to his investigation have been signed using a digital signature — not written by the congressman himself.