Nashville's city council will appoint a special committee to investigate whether there was improper use of public money during Mayor Megan Barry's extramarital affair with the former head of her security detail.

News outlets report the Metro Council voted 30-7 to create the committee, invoking an authority not used since 1974 and never against a mayor.

The council members on the committee will probe travel and overtime expenses for Barry and Sgt. Rob Forrest, who retired after they disclosed the affair.

Barry spokesman Sean Braisted says she welcomes any investigations. The mayor's office has said taxpayer dollars weren't used to support the affair.

The Tennessee Bureau of Investigation is also looking into potential misuse of public funds, focused on whether any actions violated state law.