On December 15, via Twitter, President Donald Trump announced that Secretary of Interior Ryan Zinke would step down at the end of the year. This comes after numerous investigations were initiated by the Department of Interior’s Office of Inspector General after receiving allegations of travel-related waste by Zinke’s, abuse of power, and other ethics violations.

President Trump said, “Ryan has accomplished much during his tenure and I want to thank him for his service to our nation.”

Trump said a replacement would be announced this week.

Following Trump’s announcement, in a statement on Twitter, Zinke said, “I love working for the president and am incredibly proud of all the good work we’ve accomplished together. However, 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 and Interior to focus on accomplishments rather than fictitious allegations.”

Some of the probes into Zinke included his involvement in a Montana land deal with the chairman of Halliburton and whether it constituted a conflict of interest, and a decision to not grant two tribes approval to operate a casino in Connecticut. One investigation has also been referred to the Department of Justice, but which one has not been disclosed.

The inspector general investigated several allegations of travel-related waste against Zinke, including whether his use of chartered flights and U.S. military aircraft followed relevant law, policy, rules and regulations. Another investigation focused on whether Zinke abused his position by having his family members travel with him in government vehicles, whether he asked that his wife, Lolita Zinke, be appointed as a DOI volunteer to legitimize her travel, and whether he requested a government cell phone for her. The inspector general also examined Zinke’s use of his protective service detail, including during a vacation the Zinkes took to Turkey and Greece in August 2017.

In Zinke’s two years as secretary, he rolled back numerous regulations from the former President Barack Obama era, including revoking the three-year moratorium placed on issuing federal coal leases.

In response to the announcement Thomas J. Pyle, president of the American Energy Alliance, said, “Secretary Zinke’s record stands as a testament to the Trump administration’s ‘America First’ focus. He has taken a common-sense approach at Interior that benefits all Americans by appropriately balancing the many different missions within the department.”