Nashville’s top public health official is under investigation.

Dr. Michael Caldwell, the director of the Metro Public Health Department, is the subject of an ongoing human resources investigation at city hall, Board of Health Chairman Alex Jahangir confirmed Wednesday evening.

Jahangir said he received a complaint about Caldwell and forwarded it to the city’s human resources department, which is now investigating. Jahangir declined to reveal the substance of the complaint, stating that he preferred to “let the process play out.”

Human resource investigations of city employees are confidential until they are completed, at which point some records from the investigation become public.

Caldwell has a long history of public health employment but is a new figure in the Nashville government. He took the helm of Metro Health in March, just as the coronavirus pandemic descended on the city, and initially had a prominent role in the public efforts to combat the virus. Caldwell’s public statements about the outbreak have diminished in recent months in favor of Jahangir, a Vanderbilt surgeon, and Dr. James Hildreth, president of Meharry Medical College.

This is not the first complaint against Caldwell. He occasionally squabbles with Board of Health members during monthly meetings, and back in June, the board reviewed a report about Caldwell, compiled from surveys of cabinet-level Metro Health officials, that said the director was frequently absent and had not yet familiarized himself with his agency.

Caldwell grew indignant and accused board members of “interfering” with his ability to build trust in the health department. He denied absences from the department and insisted he had worked “tirelessly” since before his job officially began.

“I am bringing together not just this department but I am bringing together this community,” Caldwell said. “I am trying to get to know everyone in this community all at once and they are trying to get to know me all at once. I am amazed at the job I am doing.”

Brian Todd, a spokesman for Metro Health, forwarded all questions about the human resources investigation into Caldwell to Shannon Hall, the city’s HR director. Hall did not immediately respond to a request for comment.