by Todd Feurer, CBS Chicago web producer; Megan Hickey contributed to this report

CHICAGO (CBS) — Two days after submitting his resignation, outgoing Chicago Public Schools Inspector General Nicholas Schuler is acknowledging some workers’ complaints about his management style “were justified,” and said he agreed to step down “so that the morale of the entire office could improve as quickly as possible.”

Mayor Lori Lightfoot accepted Schuler’s resignation on Monday. It is effective on Feb. 29.

A source close to Schuler’s office confirmed an investigation by an outside law firm has been going on for at least six months into claims he created a toxic work environment.

In a statement Wednesday afternoon, Schuler seemed to acknowledge at least some of those claims.

“I was a demanding and frequently impatient boss, and drove my employees hard, sometimes excessively hard, to achieve what they achieved. My tough management style led to complaints by employees, some of which I think were justified,” he wrote.

However, Schuler said the complaints about his behavior have been exaggerated, and he denied ever discriminating against anyone on the basis of race or gender.

Although Schuler had more than two years left on his term as the CPS inspector general, and the mayor would have had to show cause to fire him, he said he agreed to Lightfoot’s request that he resign.

“I could have contested in court whether I had truly given adequate cause to be removed. However, after careful thought, I decided that it would be better for me and better for CPS to give the resignation the Mayor requested, so that the morale of the entire office could improve as quickly as possible and everyone could fully concentrate on the oversight and student-protection missions of the office,” he wrote.

Schuler was appointed by former Mayor Rahm Emanuel in 2014, and was reappointed to a second four-year term in 2018. It’s up to Lightfoot to now choose his replacement.

On Monday, the Mayor’s office said that search would begin immediately.

Schuler said he fears there is a deficiency in the current law regarding how and when the district’s inspector general can be removed.

“This inadequacy in the IG’s governing legislation can be exploited by those who wish to corral an independent IG,” he wrote. “This is an ideal time to enact that key structural repair to the IG’s governing law, namely, codifying precisely how the IG can be removed and that removal must be for cause and only after a public hearing.”

Schuler said he’s confident Lightfoot is committed to having an independent inspector general at CPS, and expects she will appoint a “completely independent and outspoken” successor.

Schuler’s tenure as the CPS watchdog included investigations that led to the removal of two Chicago Public Schools chief executive officers.

First, Barbara Byrd-Bennett was probed for her involvement in a kickback scheme and resigned in 2015.

Byrd-Bennett was indicted for steering more than $23 million in no-bid contracts from CPS to her former employer, SUPES Academy, in exchange for $2.3 million in kickbacks. However, Byrd-Bennett never pocketed any proceeds from the scheme.

She ended up pleading guilty to one count of mail fraud, and in April 2017, she was sentenced to 4 1/2 years in prison.

And then in December 2017, CPS Chief Executive Officer Forrest Claypool ended up resigning for lying to cover for a friend.

Schuler alleged that the system’s top attorney, Ronald Marmer, violated the CPS ethics code, and that his close friend, Claypool, tried to cover up the violation.

Marmer, a former lawyer at Jenner & Block LLP, supervised a $250,000 CPS contract with the international law firm. At the same time, he was still receiving severance pay from them.

“Any other lying employee with this much evidence against them regarding lies and in different interviews would be fired,” Schuler said of Claypool in December 2017. “There would be no question about it.”

Schuler led an office of almost 50 employees.

His investigations uncovered employees falsifying work hours, disclosure of confidential student information, and irregularities in the Pre-K program – among dozens of other topics.

Most recently, an IG investigation into last school year found more than 30 instances of sexual misconduct and other disturbing behavior by teachers and others who work in the schools.