An investigation was reportedly launched, among others, into the real estate deal struck between a foundation established by Zinke and a group supported by the chairman of the Halliburton oil service company, which could have constituted a conflict of interest. Zinke’s alleged expensive flights on private aircraft were also being probed.
"After 30 years of public service, I cannot justify spending thousands of dollars defending myself and my family against false allegations. It is better for the President [Donald Trump] and Interior to focus on accomplishments rather than fictitious allegations," Zinke said in a Saturday statement.
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Zinke added that he was proud of all "the good work" he did together with US President Donald Trump.
On Saturday, Trump announced that Zinke would step down at the end of this year after two years in office.