(NewsNation) — A federal agency is now investigating the migrant flights organized by Republican Florida Gov. Ron DeSantis.

The federal Treasury Department is examining whether DeSantis improperly used pandemic aid to fund the flight of 50 migrants from Texas to Massachusetts.

According to a letter from Deputy Inspector General Richard Delmar, the Treasury Office has plans to conduct a review of the state’s COVID-19 spending.

In a letter to Massachusetts Democratic Congressional Delegation, which wrote to the IG asking for the probe, Delmar said, “We will review the allowability of use of SLFRF funds related to immigration generally, and will specifically confirm whether interest earned on SLFRF funds was utilized by Florida related to immigration activities, and if so, what conditions and limitations apply to such use.”

SLFRF funds reference the state and local funds doled out during the pandemic as part of the American Rescue Plan.

In September, DeSantis sent two planes carrying migrants to the tiny island of Martha’s Vineyard in an ongoing fight between states and the federal government over illegal immigration.

The state has not disputed that the funds it paid a charter company to shuttle the migrants were paid for out of a $12 million chunk of the interest generated from COVID-19 relief funds.

After widespread outrage from Democrats over the flights, Massachusetts lawmakers asked the Treasury Department to investigate whether that use of the funds was legal.

DeSantis said it was in line with state law and that the migrants got on the planes willingly.

According to a statement from DeSantis’ communications director Taryn Fenske:

“Weeks ago, the Office of Policy and Budget (OPB) spoke with the US Department of the Treasury’s (Treasury) Office of the Inspector General (OIG) about using interest gained from the State and Local Fiscal Recovery Funds (SLFRF) program to transport illegal immigrants voluntarily to sanctuary jurisdictions… OPB articulated to Treasury’s OIG that our use of this interest, as appropriated by the Florida Legislature, is permissible. 

But some Democratic lawmakers say this appears to be an improper use of funds.

Furthermore, Massachusetts State Rep. Dylan Fernandes (D) — whose constituents include those of the wealthy island getaway — tells NewsNation’s “Rush Hour” the migrants were lied to.

Several Democrats have asked the Justice Department to investigate claims some migrants were also misled about where they were being flown.

A lawyer filed a federal lawsuit on behalf of several migrants claiming DeSantis acted in “inhumane and repugnant conduct” when he arranged to have the immigrants transported, alleging they were “pawns” in a political stunt.