Rep. George Santos attends President Joe Biden's State of the Union address to a joint session of the Congress on Capitol Hill in Washington, DC, on February 7, 2023.
CNN  — 

More than a week after embattled Rep. George Santos named his new campaign treasurer, questions persist over the identity of the person who has filled that role and the campaign’s filings with federal regulators.

Andrew Olson, listed as treasurer of Santos’ federal political committees on February 21, does not serve as treasurer for any federal committees beyond those associated with the Republican congressman who represents parts of Nassau County, New York. And election officials in New York say no one with that name is registered as treasurer of any political committee in the state. The address associated with Olson and Santos’ campaign is that of a mixed-use apartment and commercial building in Elmhurst, New York, where the congressman’s sister resided until earlier this year.

“Do not know him. Have not heard of him,” Nassau County Republican Party spokesman Mike Deery told CNN. County GOP chair Joseph Cairo “is not acquainted (with) him,” Deery added.

On Capitol Hill on Wednesday, Santos did not answer any questions about his treasurer posed by CNN’s Manu Raju. Questions to Olson through an email address provided on the Federal Election Commission filing have gone unanswered. And Santos’ personal lawyer has not responded to inquiries.

Santos – who has lied about his biography, family background and school and work history – is the subject of federal and local investigations into his finances.

This year, questions emerged about who serves as treasurer. On January 25, Santos’ campaign listed a Wisconsin political consultant as replacing the congressman’s longtime treasurer Nancy Marks. But the consultant’s lawyer says the campaign had done so without his authorization, and his client had turned down the job.

On January 31, Marks informed the FEC that she had resigned. Later that day, Olson’s electronic signature appeared on a Santos filing that detailed the campaign’s activity in the final weeks of 2022 along with a note that said it been “filed based on the limited information provided to the campaign from the previous treasurer Nancy Marks.”

Marks did not respond to CNN’s request for comment this week. Her assistant said they don’t know who Olson is.

Confusion over filings

Confusion long has swirled around Santos’ filings with the FEC, which has sent more than two dozen letters requesting additional information from his campaign since he first ran for Congress in the 2020 election cycle.

This week, the FEC sent yet another such letter, ordering the campaign to fix the statement of organization that listed Olson as the new treasurer, because the paperwork incorrectly described Santos’ campaign committee as a national Republican Party committee. The campaign has corrected the error.

But Saurav Ghosh, a former FEC enforcement lawyer who now works with the Campaign Legal Center watchdog group, said the initial report “reflects a complete lack of sophistication and lack of diligence with the details about what they are filing.”

“It seems like his campaign has never done any of kind of reasonable job of filing accurate and complete statements, which is why the FEC has asked them so many questions and why the public, justifiably, is asking them so many questions,” Ghosh added.

Election watchdogs say they have been stumped when they have sought to learn more about Olson. “I’ve never seen this before: Having a complete mystery as a treasurer for a sitting member of Congress,” said Jordan Libowitz of Citizens for Responsibility and Ethics in Washington.

Mystery address

The address listed for Santos’ committee and his treasurer on Queens Boulevard in Elmhurst, New York, is that of an apartment building that has been associated with Santos and his sister Tiffany Devolder Santos.

The congressman’s sister vacated her apartment in that building in January, court records show, and recently reached an agreement with her former landlord to repay more than $19,000 in back rent.

Her former residence is located in a six-story residential and commercial mixed-use building on Queens Boulevard in Elmhurst – the same building that Santos has listed as his address on campaign documents. In the most recent FEC filing designating Olson as treasurer, no details are given about an office or apartment number.

Employees at the three businesses on the second floor – a Department of Labor office, beauty salon and finance firm – said the name Andrew Olson was unfamiliar. CNN was not able to access the floor, but the owner of the beauty salon said there were no other businesses or operating offices on the floor.

The congressman’s sister and her attorney did not respond to CNN inquiries this week.

State election records show Tiffany Santos controls a New York-based political action committee, Rise NY PAC, that has described itself on social media as working to boost voter registration and enthusiasm. She was paid nearly $26,000 by the PAC during the 2022 election cycle, according to filings with the New York State Board of Elections.

State elections records also show that Marks has retained her position as treasurer of Tiffany Santos’ PAC.

CNN’s Veronica Stracqualursi contributed to this story.