OMAHA, Neb. (AP) — U.S. Sen. Ben Sasse is seeking answers from the Department of Veterans of Affairs following reports that VA employees kept a secret waiting list of patients from Nebraska and Iowa that obscured the actual wait times for veterans who sought appointments.

Sasse sent a letter to the department Tuesday after the Omaha World-Herald reported that an audit included whistleblower complaints about unauthorized lists for appointments at the VA’s mental health psychotherapy clinic in Omaha.

VA officials acknowledged the audit’s conclusions but wouldn’t say how many Nebraska or western Iowa veterans were affected. They also declined to say who kept the unauthorized list and why, or say how many employees were involved.

Sasse says the agency’s refusal to answer questions is “unacceptable and must be remedied immediately.”