House Democrats opened an investigation Monday into FBI Director Kash Patel’s use of a government jet, accusing him of repeatedly taking the aircraft on personal trips during the government shutdown and demanding that he reimburse taxpayers and turn over detailed travel records.

In a letter to Patel, House Judiciary Committee ranking Reps. Jamie Raskin (D-MD) and Sydney Kamlager-Dove (D-IL) said flight records and internal accounts show Patel frequently used the FBI’s Gulfstream G550 for nonofficial excursions. Their allegations also rely on social media posts and other news articles referenced in the letter.