The Interior’s Department’s Office of the Inspector General has launched a “preliminary investigation” into Secretary Ryan Zinke after he reportedly threatened Alaska senators last week in an attempt to get them to support an Obamacare repeal push.

Reps. Frank Pallone (D-NJ) and Raúl Grijalva (D-AZ) sent a letter to the Inspector General on July 27, asking the office to look into Zinke’s calls to Sens. Lisa Murkowski (R-AK) and Dan Sullivan (R-AK).

“The OIG is undertaking a preliminary investigation into this matter. We will advise you about what further action the results of this inquiry lead the OIG to take,” Deputy Inspector General Mary Kendall said Thursday in a written response to Pallone and Grijalva.

Sullivan told the Alaska Dispatch News that Zinke called ahead of the Senate’s Obamacare repeal vote last week and threatened to sanction Alaska on energy policy if both senators didn’t vote in favor of repeal.

Murkowski had long expressed publicly that she was opposed to all the Senate GOP’s repeal proposals. She confirmed that she received a call from Zinke, but said he only told her that the President was unhappy with her vote against a motion to proceed to open up Obamacare repeal for debate on the Senate floor.

Zinke previously said claims of a threat were laughable, and on Thursday tweeted a photo of himself and Murkowski drinking a beer.

Read the letter from the Office of the Inspector General below:

