Secretary of Transportation Elaine Chao
CNN  — 

House Democrats are asking for more information about why the Department of Transportation’s top watchdog, acting Inspector General Mitchell Behm, was removed from his post earlier this month.

President Donald Trump nominated Eric Soskin, a Justice Department official, to be the department’s next inspector general on Friday, the same day State Department Inspector General Steve Linick was removed. The White House also appointed Pipeline and Hazardous Materials Safety Administration head Howard Elliott to be the department’s new acting inspector general last week, replacing Behm, until Soskin is confirmed. Elliott will continue to serve on the pipeline agency as well, a Department of Transportation spokesperson said.

The decision to name a new acting inspector general was designed to coincide with the White House’s nomination of a new candidate to become the permanent DOT inspector general, an administration official told CNN.

The official said the department had never formally named Behm as the acting inspector general, but documents reviewed by CNN show that Behm was appointed in the role in February.

House Oversight Chairwoman Carolyn Maloney (D-N.Y.), Subcommittee on Government Operations Chairman Gerry Connolly (D-Va.) and House Transportation and Infrastructure Chairman Peter DeFazio (D-Ore.) sent a letter to Transportation Secretary Elaine Chao on Tuesday opposing Behm’s removal and requesting information about any communication within the department or between the department and the White House regarding the move.

“The assault on the integrity and independence of Inspectors General appears to be an intentional campaign to undermine their ability to expose corruption and protect taxpayer dollars from waste, fraud, and abuse,” the letter from the committee chairmen states.

Inspectors general serve as an internal agency watchdog. They investigate their own department’s potential wrongdoings and ensure that there is a check on the department using taxpayer money for public work and programs.

The committees said Elliott is unqualified to be the Transportation Department’s acting IG because he has little to no law enforcement experience, while Behm has been working in the department’s IG office since 2003. The department spokesperson contradicted this, pointing to Elliott’s experience serving as a commissioned railroad police officer and graduating from the Indiana Law Enforcement Academy.

The committees also opposed Elliott’s appointment while he continues to serve as the head of the Pipeline and Hazardous Materials Safety Administration. They said it would “severely chill” whistleblowers from coming forward to the office.

“Under this troubling arrangement, Mr. Elliott would report to you as PHMSA administrator while simultaneously serving in a role that is required by law to be independent,” the letter states. “Whistleblowers might fear that their identities could become known to an official still reporting to you.”

The department spokesperson said they “would expect” Elliott to recuse himself from investigations and audits involving his own agency, which is part of the Department of Transportation.

Last October, the House Transportation and Infrastructure Committee asked the IG’s office to investigate Chao’s “possible conflicts of interest,” including various reports that her office was giving “preferential treatment to Kentucky.” Chao’s husband, Senate Majority Leader Mitch McConnell, is a Kentucky Republican.

“The department has previously fully responded to this issue, a politically motivated waste of time. While the department will always be cooperative and responsive to appropriate requests, DOT looks forward to a final resolution of these questions,” the spokesperson said regarding the investigation into Chao.

CNN’s Jeremy Diamond contributed to this report.