The Department of the Interior’s internal watchdog office has concluded that it cannot determine whether an unusual and controversial reassignment of dozens of senior employees ran afoul of federal law — because top Interior officials failed to document how they made their decisions.

The report from Interior’s inspector general’s office highlights the latest example of department leaders keeping scant records of their personnel and spending decisions — a practice that has drawn scrutiny from congressional overseers and environmental groups. The Washington Post obtained a copy of the report from two separate sources before investigators published it later on Wednesday.

The investigation began after Democratic lawmakers raised concerns about Interior Secretary Ryan Zinke’s move to reassign 27 members — about 12 percent — of his department’s workers in the Senior Executive Service between June and October.

Individual reassignments are common for members of the SES, a corps of top career and politically appointed federal employees who serve just below top presidential appointees.

But the mass transfer — which came without prior notice and forced some senior workers to move across the country  — caught longtime Interior employees and some members of Congress off guard, especially given the scarcity of confirmed political appointees in the department at the time.

In the new report, Deputy Inspector General Mary Kendall of Interior found that the members of a board set up to make the transfer decisions in May did not follow the correct protocol for record-keeping. The Executive Resources Board, Kendall’s report found, “did not document its plan or the reasons it used when selecting senior executives for reassignment, nor did it gather the information needed to make informed decisions about the reassignments.”

Without documentation including “meeting minutes, notes, voting or decision records,” investigators were not able to determine whether the board’s decisions complied with federal law to protect employees from sudden transfers. Interviews with those making personnel decisions did not yield an explanation. “When we asked the ERB members who in the Department leadership ordered the reassignment of senior executives, no one could provide an answer,” the report read.

In a statement, Interior spokeswoman Heather Swift said the inspector general report validated the department’s personnel decisions. “Obviously, the evaluation confirmed the Department’s long-held view that the ERB has the lawful authority to reassign SES Members and has done so here,” she wrote.

But at least one of member of the SES who was reassigned in Zinke’s mass transfer held up internal investigators’ findings as an example of ineptitude at Trump’s Interior Department.

“I am stunned by the level of incompetence that this report describes; there were so few records kept that the Inspector General can’t even make a determination of the legality of the reassignment actions,” said Joel Clement, an Interior executive-turned-whistleblower who resigned in October. “It’s remarkable that the political staff at Interior would be so blithe, thoughtless and careless during a time of intense scrutiny. It begs the question, what did they have to hide?”

In a March memorandum, David Bernhardt, Zinke’s top deputy, conceded to Kendall after reviewing her report that while they believe the personnel decisions were lawful, “the Secretary and I concluded that the ERB could benefit from incorporating best practices and improving its business process.”

It is not the first time that the Trump team’s record-keeping has raised flags from the inspector general’s office. In November, the IG issued another alert notifying department officials that its audit of Zinke’s travel practices had been hampered by “absent or incomplete documentation for several pertinent trips.”

In this case, Zinke’s attitude toward longtime Interior employees drew special scrutiny after the secretary claimed that nearly a third of his staff is disloyal to Trump in a speech to a federal advisory board dominated by oil and gas industry executives. “I got 30 percent of the crew that’s not loyal to the flag,” the secretary said, according to participants.

Clement was removed from his job as director of policy analysis, working on the effects of climate change on Alaska Native communities, and reassigned to a revenue accounting position for which he said he had no experience.

In a July op-ed in The Post, Clement said he believed he was reassigned because he spoke out about human-caused global warming, which Trump and many members of his administration have dismissed as untrue despite major scientific consensus on the subject.

“Behind this whole Keystone Kop display of incompetence,” Clement said in an interview Wednesday, “there’s this determination to purge the agency of anyone who doesn’t support the secretary’s flag.” In total, 12 reassigned Interior employees interviewed by the inspector general’s office, including Clement, said they believed they were transferred because of prior work on climate, conservation, energy and other issues.

Another transferred SES employee at Interior, who declined to be named for fear of further reprisal, said the “investigation is vindicating for my colleagues and me. In my opinion it confirms we were the victims of ego and personal vendettas.”

Democrats seized on the report as confirmation that the Trump administration sought to “punish” career staffers at Interior.

“This report backs up my concern that Interior Department leaders identified employees for reassignment as a way to punish career staff who were working on issues that contradicted the administration’s anti-science agenda, particularly its climate denial campaign,” said Sen. Tom Udall (N.M.), the top Democrat on the Appropriations subcommittee overseeing Interior.

The inspector general’s office made recommendations to improve record-keeping, including estimating the cost of all geographic transfers and writing out a plan for reassigning senior personnel “to ensure accountability.”

Already, Interior carried out its own changes by drafting a formal charter for the ERB and restructuring the board to include a mix of career and non-career employees. Previously, all six members of the board were political appointees.

Interior’s inspector general opened the probe at the request of Democrats on the Senate Energy and Natural Resources Committee, led by Sen. Maria Cantwell (Wash.), that committee’s ranking Democrat, as well as Udall.

“We are concerned that mismanagement of this program could lead to premature retirements, lower morale within the federal workforce, higher costs for the Department, and discourage talented professionals from entering the SES,” Cantwell and other congressional Democrats wrote last month in asking yet another investigative bureau, the U.S. Government Accountability Office, to look into the reassignment issue.