Interior Department investigators are probing Secretary Ryan Zinke’s use of private charter flights.

Zinke disclosed last week that he has taken three charter flights, including a $12,375 late-night trip from Las Vegas to his home state of Montana.

A spokeswoman for the department’s inspector general’s office, Nancy DiPaolo, confirmed the office is investigating.

Zinke is one of several Cabinet members facing questions about travel after Tom Price resigned as health chief for blowing through about $1 million in taxpayers’ cash on government and private flights.

Zinke said Friday that “taxpayers absolutely have the right to know official travel costs,” but he dismissed criticism of his flights as “a little BS over travel.”