Trump's inauguration cost a record $107M—more than twice as much as Obama's '09 inauguration.

New documents obtained by CNN show a former adviser to Melania Trump was among those who raised concerns about excessive spending in the lead-up to the events: https://t.co/HOsSjWwzGe

Event planner Stephanie Winston Wolkoff has emerged as a witness for investigators. A subpoena she received last month asks her to hand over a variety of information, including evidence of expenditures that were "wasteful, mismanaged, and/or improperly provided private benefit."

Of note: The subpoena asks not just for communications between the inaugural committee and business entities connected to President Trump, but also communications between Wolkoff and Trump family members including Ivanka, Don Jr, Eric, and Jared Kushner.

The DC subpoena is the third Wolkoff has received about the inaugural's finances. Two people close to Wolkoff tell CNN that she has responded to the latest subpoena.

That could be worrisome for people connected to the inauguration.