NASHVILLE (AP) — Nashville's internal auditing office will investigate travel and overtime expenses being questioned because of Mayor Megan Barry's affair with the former head of her security detail.

The Metro Nashville Audit Committee voted 6-0 Tuesday for the city auditor to work with a seven-member council committee investigating the affair.

The audit coincides with three state and local investigations into the affair between Barry and retired Sgt. Rob Forrest. Barry has said the affair began several months after she came into her administration in September 2015. She has said the affair has ended, but hasn't said when.

The mayor's office has said it welcomes investigations. The office contends taxpayer dollars weren't used to support the affair.