Senate Democrats have called for an investigation into the reported removal of Kenneth Kies, the acting chief counsel at the Internal Revenue Service. They say he was forced out after objecting to White House efforts to influence audits of particular taxpayers, raising concerns that political pressure may have compromised the tax agency’s independence.

Twelve Democratic senators asked the Treasury Department’s inspector general to examine whether White House officials broke federal law and whether Kies’s departure was retaliation. US law prohibits the president, vice president and their staff from directing the IRS to start or end an audit or investigation of a named taxpayer, a safeguard intended to prevent political misuse of tax enforcement.