An 11th former Biden administration aide is appearing before House Oversight Committee investigators on Thursday morning as Republicans continue to investigate allegations of a "cover-up" in the previous White House.Ian Sams is a longtime Democrat communications operative who most recently served as a senior spokesman for former Vice President Kamala Harris' 2024 campaign.Before that, he served as a senior advisor and spokesman for the White House Counsel's Office under former President Joe Biden, where his primary role entailed responding to congressional probes mainly launched by Republicans.RON KLAIN DODGES REPORTERS AFTER MARATHON GRILLING IN BIDEN COVER-UP PROBE"You were a first line of defense to spin negative stories about the president and his mishaps," House Oversight Committee Chair James Comer, R-Ky., wrote to Sams in late June.He pointed out that Sams' tenure in that role, which lasted from May 2022 to late August 2024, stretched across much of the latter half of Biden's term."The scope of your responsibilities both official and otherwise and personal interactions within the Oval Office cannot go without investigation, given the mounting evidence that President Biden was incapacitated for much, if not all, of his single term," Comer wrote. "If White House staff carried out a strategy lasting months or even years to hide the chief executives condition or to perform his duties Congress may need to consider a legislative response."LONGTIME BIDEN AIDE SAYS HE STOOD TO EARN UP TO $8M HAD PRESIDENT WON RE-ELECTIONComer's committee is investigating whether Biden's top White House aides covered up signs of mental decline in the former president from both the media and fellow Democrats.Of particular interest to House investigators is the myriad clemency orders that Trump signed in the latter half of his four-year term, and whether those decisions and others signed via autopen were made with Biden's full awareness.Biden maintained he "made every decision" in a recent interview with The New York Times.Sams was also notably thrust into the spotlight during his time as a Harris 2024 spokesman after being called out by name by President Donald Trump."Sams is just a below-average guy, with memorized FAKE NEWS soundbites, almost all of which are WRONG," Trump wrote on Truth Social after one of Sams' appearances on Fox News Channel last year.While Sams is the 11th former Biden White House aide appearing, he is just the eighth to come in for a voluntary interview.Three other former Biden officials ex-White House physician Kevin O'Connor and former senior advisors Anthony Bernal and Annie Tomasini were compelled to appeal via subpoena.Like the sit-downs before his, Sams' interview will be taking place behind closed doors and is expected to be led by lawyers for both Republicans and Democrats on the committee.