Michigan Gov. Gretchen Whitmer‘s use of a private plane to travel out of state in March could soon be facing multiple investigations.

Rep. Steve Johnson, the chairman of the Michigan House Oversight Committee, said there may even need to be an inquiry into the financial arrangements behind Whitmer’s visit to her father, who is reportedly chronically ill, if her administration is not forthcoming in response to the committee’s letter, which Johnson’s office said will be sent this week.