CHICAGO (CBS) — The Chicago Public Schools have suspended a controversial $20.5 million contract with a company that provides leadership training to principals, amid a federal investigation of the company’s ties to CPS Chief Executive Officer Barbara Byrd-Bennett.

Chicago Board of Education Vice President Jesse Ruiz, who is stepping in as interim CPS CEO while Bennett takes a leave of absence, sent SUPES Academy a letter informing the company to immediately cease all activities under its contract, and to preserve all records in connection with the contract.

Ruiz previously said he is ending the use of no-bid deals at CPS, and if wrongdoing is found in connection with the SUPES contract, CPS legal counsel is preparing options to terminate the deal.

Byrd-Bennett, along with at least three other CPS aides, is a focus of the federal probe, along with the Wilmette-based SUPES Academy, which offers leadership training to principals. SUPES received a $20.5 million no-bid contract in 2013, right after CPS closed 50 schools.

The three other CPS officials are: chief of staff Sherry Ulery; Tracy Martin, head of strategic services; and Rosemary Herpel, a senior project manager.

Sources tell CBS 2 it was Byrd-Bennett who strongly pushed the Chicago Board of Education to hire SUPES Academy to do principals training, arguing only that firm was qualified to fill that task.

The district is also planning to hire an outside firm to review the sole-source contracting process that led to the deal with SUPES, “as well as provide concrete recommendations on how it could be improved in order to ensure the full integrity of the sourcing decision,” according to documents provided by CPS.

Ruiz halted awarding any new no-bid contracts but insists the SUPES deal, which he voted for, wasn’t a mistake.

“Given the information I had at that time, I was comfortable making that vote,” he said.

SUPES spokesman Dennis Culloton said the company is disappointed to learn its contract is being suspended.

“We stand behind the training we provide, bolstered by the positive feedback we have received from these same principals. We are committed to continuing our great work with CPS once this review is completed,” Culloton said in an email.

Byrd-Bennett’s bio states she’d been a coach and trainer for SUPES Academy before she was hired to run CPS, but her economic interest forms don’t mention it.

In 2012, she claimed no outside income. Yet she was listed as a senior associate for PROACT, owned by the same man who owns SUPES.

In 2013, she listed three outside jobs paying more than $1,200: Homer Glen’s Education Research Development Institute, where today she’s listed on its website as a senior advisor; the Broad Institute in Los Angeles, as an executive coach; and the Pittsburgh Public Schools.