CHICAGO (CBS) — Chicago Public Schools CEO Forrest Claypool apologizes no fewer than four times for lying to ethics investigators and other missteps –- actions that have prompted some to call for his termination.

“I made a mistake,” Claypool said in a statement released Thursday.

He admits he “misread the situation, and made mistakes in judgment.”

A scathing report finds Claypool repeatedly lied and altered records to mask the true purpose of a bill for legal advice.

After a 14-month investigation, CPS Inspector General Nicholas Schuler says he had no choice but to recommend Claypool be fired.

“Any other line employee with this much evidence against them regarding lies in two different interviews would be fired. No question about it. So, I don’t think there can be a lesser standard for the CEO,” he says.

At the heart of the probe: Claypool’s defense of Ronald Marmer, the top CPS attorney. Marmer managed legal work provided by firm Jenner & Block, even though Marmer used to work for that firm and was still receiving payments from them.

Six attorneys — four inside CPS and two outside — all called that a conflict of interest, an ethics violation. Schuler says Claypool was so desperate to hide those opinions from the school board he changed the bill from one of the outside attorneys and then lied about it.

“Administratively, you cannot lie to the IG and keep your job,” Schuler says.

Also Thursday, Mayor Emanuel continued defending Claypool but dodged a reporter’s follow-up question about the matter.

“There are always two sides and Forrest deserves the right to be heard and he is preparing to have that heard,” the mayor said. “I will also say and I want to remind everybody of my third point, and that is, that Forrest acknowledged he made a mistake.

“He acknowledged where he was wrong and took responsibility for it. That is a sign of character and he did it in a very public way; so you know what I said yesterday, there is nothing for me to add or change that.”

When Chicago Tribune reporter John Burns pressed Emanuel about whether Claypool engaged in a cover-up, the mayor was already walking away.