To speed the process along, Bottoms said she had sought help from the Georgia Municipal Association to identify a consultant to conduct the audit and to keep a potential Gulch vote from being delayed.

Atlanta Mayor Keisha Lance Bottoms. (ALYSSA POINTER/ALYSSA.POINTER@AJC.COM)

Eight council members, a voting majority, sponsored the audit legislation. But three, including one sponsor, council members were absent from Monday’s meeting, and co-sponsor Michael Julian Bond was not in the room when the vote was taken. It ended up two votes short of the eight needed to pass.

Several community groups spoke in favor of the audit, while others urged council to reject the deal, saying promises of affordable housing and other public benefits weren’t sufficient.

“We are depending on the numbers and the word of a developer that is in line to take billions of dollars in public money,” said former state Sen. Vincent Fort, an opponent of the deal. “I can see why CIM doesn’t want an independent review. What does the mayor and council have to hide?”

A rendering from developer CIM Group shows a new plaza within the redeveloped Gulch.

To make the site feasible, it requires constructing massive $500 million steel and concrete platform spanning 40 acres that CIM has said it will pay for.

But the company wants to use future tax dollars created on site to help ensure investor returns.

The proposal relies on bonds backed by two sources of public funding: 5 cents of the city’s 8.9-cent sales tax generated from future sales on the Gulch site, and future expected increases in property taxes from the development, which lies in a zone known as a tax allocation district.

Four of the five cents are state tax dollars. The overall financing, CIM co-founder Richard Ressler has said, would come at no credit risk to the city because CIM is on the hook for the debt if the tax dollars don't cover all the bonds.