In a rare move, Mayor de Blasio on Friday fired Department of Investigations Commissioner Mark Peters.

Earlier this year, Peters opened a probe of an independent office that conducts investigations of the school system.

The head of that office was fired, and went on to file a whistle-blower complaint against Peters.

The mayor said an independent investigator found Peters conducted himself in a quote, "manner indicating a lack of concern for following the law,” and made “deliberately misleading statements."

Peters has uncovered significant wrongs in de Blasio's administration, including lead paint in public housing.

Peters was appointed as commissioner after serving as de Blasio's campaign finance chair during his 2013 run for Mayor.

Margaret Garnett was nominated by the Mayor to serve as Commissioner.

Garnett currently works as the state’s executive deputy attorney general for criminal justice.