A third big issue that has also reportedly drawn the attention of prosecutors is how the committee spent the money it raised.
According to the committee, its finances "were fully audited internally and independently and are fully accounted. Moreover, the inauguration's accounting was provided both to the Federal Election Commission and the IRS in compliance with all laws and regulations."
But the 990 Form that the nonprofit committee submitted to the IRS in October of last year sheds little light on where the money actually went.
According to the filing, $76 million was spent on "conferences, conventions and meetings." But there's no accounting for who actually got that money.
To be clear, nonprofits are not required to disclose each of their vendors, only the top five. In this case, the top five contractors hired by the committee collected a total of $62 million out of the $104 million the committee reported having spent on the inauguration.
Prosecutors are now looking at where some of that money went, according to reports.
On Friday, ProPublica reported that some of it went to Trump's businesses for venue rentals, in transactions that were brokered in part by the president's daughter, Ivanka Trump. According to ProPublica, even before the inauguration, there were already concerns being raised internally about whether the Trump Organization was overcharging the inaugural committee for event space.
According to a spokesman for Ivanka Trump's lawyers, she "passed the inquiry on to a hotel official and said only that any resulting discussions should be at a 'fair market rate.'"
But the issue of whether or not the committee was overcharged by its vendors could be part of another central question: How Trump's inaugural committee managed to spend more than double the amount of money that previous presidents spent to put on so many fewer official events than previous presidents held.
Not only did Trump hold three official balls, as opposed to Obama's 10, he also shortened the presidential inaugural parade to just 90 minutes, down from more than two hours for his predecessor.
Trump also had fewer musical acts to pay for. After struggling to book talent to play his inauguration after a bitter and divisive election campaign, Trump's final talent lineup included former teen singer Jackie Evancho, the Radio City Rockettes and the Mormon Tabernacle Choir.
As for Trump's now infamous comparison of the crowd sizes for his actual swearing-in outside the Capitol, most of those expenses, regardless of crowd size, are covered by the Joint Committee on Inaugural Ceremonies, which is overseen by Congress and funded by taxpayers.
At the time of Trump's inauguration, some organizers said the haphazard nature of the planning meant the committee was unable to competitively bid out the contracts for venues and catering, leaving them subject to whatever vendors wanted to charge.
Nonetheless, it's difficult to see how last minute surcharges could explain how twice as much money was spent on what appears to have been about half as many events. To date, the committee has not offered any accounting for the additional $42 million it spent on vendors who were not among its top five.