The head of the city’s Department of Investigations is leaving for a position as deputy U.S. Attorney, just days after her department released a report into Mayor Bill de Blasio’s alleged misuse of public resources in both his failed presidential campaign and for his family’s personal life.

Margaret Garnett, the commissioner of the DOI since 2018, will be the deputy attorney in the office of U.S. Attorney for the Southern District of New York Damian Williams, the DOJ announced Wednesday. She steps down November 10th and First Deputy Commissioner Daniel Cort will serve as acting Commissioner.

Last week, the DOI released a 47-page report after a two-year investigation that found that city taxpayers have paid for about $320,000 of the mayor’s security expenses during his brief presidential campaign in 2019, despite clear rules that would block the use of resources on political activity.

“Either it’s not good security, or it’s not good government, or both,” Garnett said last week at a press conference to announce the report.

The investigation also uncovered a range of ethics breaches related to the mayor’s security detail. The report said the detail’s assigned officers helped move his daughter Chiara’s furniture, and drove his son Dante to Yale (when Dante was a student there) and, more recently, to his job in Brooklyn.

De Blasio has so far declined to reimburse the city, a potential ethics violation that could impair his rumored gubernatorial run. It will be up to the city’s Conflict of Interest Board to determine whether de Blasio is forced to reimburse the city for the $319,794.20 spent on travel costs for his security detail during the presidential primary.

According to de Blasio’s press secretary, the city is currently appealing the board’s previous determination on campaign-related expenses, and no final decision has been made.

De Blasio has maintained he and his family faced unique security requirements and they followed NYPD guidance.

“When I walked in the door as mayor. I didn't know what the security protocols were,” de Blasio said Wednesday at his press briefing. “I didn't know what the approach had been historically. I only knew and assumed that it would follow what had happened for other mayors.”

He also told WNYC's Brian Lehrer that the report was "unbelievably inaccurate and unfair."

The DOI report could also carry criminal consequences for the mayor’s head of security, NYPD Inspector Howard Redmond, who allegedly “obstructed and sought to thwart this investigation” by destroying his phone and refusing to turn over records. Garnett said last week that Redmond’s conduct has been referred to the Manhattan District Attorney Office.

Garnett joined the DOI after the previous commissioner, Mark Peters, was fired by de Blasio. Peters later claimed that he was pressured not to release reports that would criticize the de Blasio administration, telling the City Council that the mayor, during a phone call, "yelled at me, accused me of trying to bring his administration 'down' and then informed me he was 'going to hang up now before I say something I shouldn't.'"

In her resignation letter, Garnett acknowledged she joined the DOI "at a time of upheaval and crisis," and that she only accepted de Blasio's nomination "on the condition that I would be permitted to exercise DOI's lawful authority guided only by my independent professional judgment and the public interest."

She previously worked for the DOJ as an Assistant U.S. Attorney for 12 years, serving at times as Chief of Appeals and Chief of the Violent and Organized Crime Unit, according to a press release.

Williams said he was “pleased” to bring Garnett back to the Justice Department.

“Margaret was a legendary Assistant U.S. Attorney. During her time in the Office, she led some of the Office’s most important investigations and prosecutions, and mentored countless (Assistant U.S. Attorneys),” he said in the press release. “Her storied career in public service leaves no doubt that she will be an exceptional Deputy U.S. Attorney.”

Williams also announced the appointment of former Assistant U.S. Attorney Daniel Gitner as Chief of the Office’s Criminal Division.

[Update: Mayor Bill de Blasio's office sent a statement Wednesday on Garnett's new position:

“Commissioner Garnett stepped up to serve this City and DOI when they needed it most, and I’m grateful for her tireless efforts," de Blasio said in the statement. Our country is gaining a skilled and devoted US Attorney in Damian Williams, and Commissioner Garnett’s experience, passion and work at the DOI will serve her well in this new role.”]