An Air National Guard crew’s overnight stay at President Trump’s resort in Scotland during a routine military trip is under scrutiny by the House Oversight Committee, Politico reports. Sources cited in the report say crew members of the C-17 transport plane stayed at Trump’s Turnberry resort both on the way to Kuwait to deliver supplies and on the way back to the U.S. in the early spring. The crew’s stop at the resort, which is located about 50 miles from Glasgow, stands out from previous supply runs, when the C-17 typically landed at U.S. air bases or near U.S. military sites to refuel, according to Politico.

The House Oversight Committee has reportedly been probing the trip since April as part of a broader investigation into U.S. military expenditures and whether they have been used to benefit Trump’s businesses. In a letter to Acting U.S. Defense Secretary Patrick Shanahan in June, House Oversight Committee chairman Elijah Cummings raised concerns over the U.S. military spending $11 million since October 2017 on fuel at Prestwick Airport, the airport closest to Trump’s resort which Cummings described as “integral to the golf course’s financial success.” The Turnberry resort lost $4.5 million in 2017 but saw revenue climb $3 million in 2018.