Exterior of a Department of the Interior office building in Washington. (Jahi Chikwendiu/The Washington Post)

The Department of the Interior’s internal watchdog office has concluded 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 the inspector general’s office of the Interior Department 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 new report from two separate sources, and it is expected to be released to the public on Thursday.

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 of last year.

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 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, the Interior’s Deputy Inspector General Mary Kendall 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 this documentation, investigators were not able to determine if the board’s decisions complied with federal law to protect employees from sudden transfers.

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 yet another 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 has since resigned. “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?”

It’s also 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 its audit of Secretary Ryan 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 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.

Interior’s inspector general opened the probe at the request of Democrats on Senate Energy and Natural Resources Committee, led by its ranking member Sen. Maria Cantwell (Wash.).

“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.

This post will be updated.