NEWARK — A controversial consultant’s report recommending that some of Newark’s worst public schools be replaced with charter schools was funded by a $500,000 grant from a California educational foundation at the behest of Mayor Cory Booker.

The revelation came in an interview with officials at the foundation late Wednesday. It followed two days in which the mayor declined to provide details about the report: who funded it or the amount spent on it.

Contacted by the Star-Ledger, the spokeswoman for the Broad Foundation in Los Angeles readily acknowledged it put up the money that was used to retain Global Education Advisors to conduct an audit of the city’s schools. The spokeswoman said she wondered why the grant was kept secret.

The consulting firm, incorporated by Christopher D. Cerf before he was named the state’s acting education commissioner, has itself become the focus of growing questions over its ties to the commissioner and the mysterious way it was selected.

The grant disclosure came on a day when there were several developments in the mystery of Global Advisors.

The acting commissioner gave a revised account of his ties to the firm — acknowledging he had been more involved than he first indicated earlier this week. Cerf had first maintained he had done little more than lend his address for the incorporation papers.

State campaign finance records also show Cerf gave a $1,000 contribution to the re-election campaign of Booker just a month before Global Education Advisors was incorporated by Cerf.

Cerf says his motives have been mischaracterized.

“This was entirely driven by an impulse and my desire to support Newark public schools as they move toward reform.” Cerf also did a long interview Wednesday with Star-Ledger columnist Bob Braun. It appears in today’s Op-Ed section.

At issue are concerns some have raised over whether Cerf would be conflicted as commissioner by his connections to a firm whose recommendations he may have helped draft or inspire. If implemented, the proposals call for closing or consolidating several Newark schools whose students continue to fail year after year, replacing them with charter schools and some new district schools throughout the city. Critics say because of the ties, Cerf could end up being on both ends of the reform process in Newark: The company founded by Cerf the reformer makes proposals that are then approved by Cerf the commissioner.

The continuing questions and new revelations about the ties between Cerf, his former consulting firm, and the mayor — drawn from state campaign finance reports and interviews with city advisory board officials and others — came as parents and educators continued to rally against the recommendations that would remake the city’s school system.

Cerf said Wednesday there was no conflict with his involvement with Global Education Advisors, or his support of Booker, and reiterated that he severed his connections as soon as he was nominated.

A spokesman for Gov. Chris Christie said Cerf fully disclosed his ties to Global Education Advisors and described his involvement to the governor’s office.

“He explained it to us during the vetting process and that he would be ending the association. We were completely satisfied by that,” said the spokesman, Michael Drewniak. “It has no conflict with his nomination to be education commissioner.”

However, Cerf’s public explanations varied from earlier statements just a day earlier, when he said he had done little more than lend his address for the incorporation papers.

He said Wednesday he had been involved more directly with the company during a brief period around Thanksgiving when it began working on an analysis that would count enrollment, facilities and student achievement. Cerf said the work did not begin in earnest until around December.

“Several weeks later I resigned,” he noted. He was nominated for commissioner on Dec. 20.

Until then, he said his role was simply to conduct fact-based studies of the Newark Public Schools. He added that he had no role in drafting the recommendations that have generated so much concern by parents and educators.

“I never even saw it until a few days ago,” he said.

He called his campaign contribution to Booker neither improper or unusual, adding that he had also contributed money to the school board campaign of Shavar Jeffries.

Newark school board officials said it was clear to them that Cerf was involved more deeply in the company before his departure. Advisory Board Vice Chairwoman Barbara King said the board’s leadership only became aware of Global Education Advisors and their work in the district after that work had begun, and they had a sit-down meeting with Cerf and Rajeev Bajaj, who now runs the consulting firm.

King also said she and Jeffries fought for face time with the consultants after learning of their mission.

“Everything was kept in secret,” she complained. “We never knew about these schools that would close. If we had known, we could have involved the community. No one wants to learn things after the fact.”

When they met in November, King said the consultants told the board members they were doing no more than gathering diagnostic data about the school district.

Booker yesterday again said he did not know how much Global Education Advisors was paid to do consulting work, although he said he looked at several different firms and settled on Bajaj because he had consulted with Newark in the past.

“We didn’t want to go with someone who was starting from scratch,” Booker said.

The mayor confirmed that the grant money came from Broad but declined to say who was in charge of contracting the consulting firm, though he said it was not him. However, the Broad Foundation said the money was channeled to the Foundation for Newark’s Future, the nonprofit created to raise $100 million to match Facebook CEO Mark Zuckerbeg’s gift to the city.

“We were in conversations for months about how we could help leaders in Newark, and we were asked if we could support an audit of the district,” said spokeswoman Erica Lepping. “The purpose is to make sure local leaders have a factual basis for making decisions about reform.”

Lepping said Global Education Advisors had been selected by the Foundation for Newark’s Future, but could not say on what grounds the consultants were selected.

The Broad Foundation funded similar audits of other urban school systems, she said, most recently in Washington, D.C., and Detroit.

Lepping noted as well that the audit was not intended to make recommendations, just assert facts.

By Jessica Calefati and David Giambusso/The Star-Ledger

Staff writers Jeanette Rundquist, Bob Braun and Ted Sherman contributed to this report.

The Montclair home of acting N.J. Education Commissioner Christopher Cerf, which also serves as the mailing address for a foundation he incorporated.