South Dakota Gov. Kristi Noem is under investigation for allegedly using a state-owned plane to ferry her to personal events, like her son’s prom, ABC reports. The state’s ethics board has referred the tips to the state’s Division of Criminal Investigation and a county prosecutor will now determine if the star Republican governor violated a 2006 state law about official travel. In one of several questionable trips referred to the ethics board, Noem spent $3,700 in taxpayer funds to take a last-minute trip home to see her son go to his high school prom. She also reportedly used the state plane to attend six out-of-state political events, including those organized by the National Rifle Association and Turning Point USA, and also brought family members along with her. Noem’s campaign spokesperson, Ian Fury, defended some of the trips as “returning from official travel,” and said it was “fully within precedent” for family members to travel with her.