Trump told his aides that he is afraid Zinke has broken rules while serving as the interior secretary and is concerned about the Justice Department referral, according to the officials, who spoke on the condition of anonymity due to the sensitivity of the matter. But the president has not indicated whether he will fire the former Navy SEAL and congressman and has asked for more information, the officials said.

This week, Interior’s Office of Inspector General referred the inquiry — one of several probes into the secretary’s conduct — to the Justice Department to determine whether a criminal investigation is warranted. That referral concerns Zinke’s involvement in a Whitefish, Mont., land development deal backed by David J. Lesar, chairman of the oil services firm Halliburton.

The business and retail park, known as 95 Karrow, would be near parcels of land owned by Zinke and his wife, Lola. The inspector general is looking at discussions Zinke had with Lesar and others about the development that could indicate he was using his office to enrich himself.