The Department of Investigation is often overlooked and underappreciated. Mayor Mamdani should change that.
Very few mayors love the city’s Department of Investigation. There are understandable reasons for this. When the department makes headlines, it is rarely good news for the mayor. For example, in recent years, the Department of Investigation (DOI) in New York City has played a major role in the explosive investigations of Mayor Eric Adams and his top aides for corruption.
Despite the potential that DOI could train its sights on his administration, Mayor Zohran Mamdani should actively seek to bolster DOI’s independence. A reimagined DOI would not only be very good for New York; it can become a model for how the federal government can reinvent the role of inspectors general going forward.
At the federal level, IGs prevent and combat fraud, waste and abuse through audits, investigations and recommendations. IGs are appointed by the president, but report to both the president and Congress. Their removal requires prior notice to Congress. Historically, IGs have not been subject to turnover during changes of administration.
Right now, federal IGs face an existential threat.
In January 2025, President Trump took the unprecedented step of firing 17 IGs en masse at the end of the first week of his second term in office. And when the U.S. Agency for International Development IG appropriately exercised his jurisdiction by publicly reporting on the negative effects of freezing funding and mass firing at that agency, the president retaliated by firing him as well. Subsequently, Trump has appointed IGs with records of ethical lapses and political partisanship, leading many to question their independence. All this has left accountability and oversight of federal agencies in shambles.
New York City can write a different story. Under the New York City Charter, DOI — led by an official appointed by the mayor with consent of the City Council — is charged with making any investigation directed by the mayor or Council as well as any study or investigation which the DOI commissioner believes to be “in the best interests of the city.” The Charter also mandates DOI’s specific investigative responsibilities for three high-profile city agencies — the police department, the Department of Correction and the New York City Housing Authority. All City department IGs report to DOI.
DOI has often played a primary role in the criminal investigation of municipal corruption cases. The agency has subpoena power and a staff that includes criminal investigators. In 2024, DOI made 370 arrests and 498 referrals for criminal prosecution.
Crucially, in recent years, DOI has maintained its independence even as it helped lead criminal investigations of the mayor that it reported to.
Before the Trump Justice Department withdrew the prosecution, Eric Adams was the first New York City mayor in over 150 years to be indicted while in office. That was in no small part due to the dogged investigations of DOI, led by then-Commissioner Jocelyn Strauber. Strauber joined with the U.S. Attorney for the Southern District of New York and the FBI in announcing the indictment. U.S. Attorney Williams specifically praised the outstanding work of DOI in the case and Commissioner Strauber noted that DOI’s “unique access to City records and expertise in matters of City government make us a critical partner” in the investigation.
According to Strauber, at no time was the independence of DOI under threat. This was a remarkable testament to DOI’s independence, and it stands in stark contrast to the state of federal IGs under Trump.
In prior administrations, DOI’s independence has been questioned.
Mayor Rudy Giuliani appointed a long-time friend, Howard Wilson, as his first DOI commissioner. DOI was removed from an investigation into the award of $43 million in city contracts after federal authorities said the inquiry, which had reached into the mayor’s cabinet, had been put at risk because Wilson had briefed Giuliani on the investigation’s progress.
Mayor Bill de Blasio’s initial appointment to DOI, Mark Peters, was denounced because Peters had previously served as DeBlasio's campaign treasurer. De Blasio eventually fired Peters after a damning investigation of his conduct at DOI — but also after the agency had issued a series of critical reports of the administration. The Peters case is an interesting one — it raised concerns about independence based on both the prior relationship of the commissioner and mayor and the removal of a commissioner after DOI fulfilled its oversight role.
Rather than relying on mayors and DOI commissioners to do the right thing, Mayor Mamdani and the Council should take strong steps to enhance DOI’s structural independence.
Right now, the City Council must confirm the DOI Commissioner, and the mayor can only remove the commissioner after a public statement of cause. Those are essential features safeguarding DOI’s right to act as it sees fit. But a series of additional guardrails could further guarantee the agency’s independence.
DOI commissioners could be appointed for a fixed term that does not overlap with the mayor’s term. City Council review could be required before any removal takes place. In the event of a vacancy in the commissioner’s office, it should be filled by a chief deputy who was also subject to City Council approval.
Beyond that, the Mayor and Council and DOI leadership should reimagine and reinvent DOI’s role so it does more to make city government honest, efficient, effective and fair. This would be aligned with DOI’s broad powers delineated in the City Charter, which go beyond the investigation of corruption to include “the affairs, functions, accounts, methods, personnel or efficiency of any agency.”
First, DOI should focus on making City government work for those who need it most. Pervasive economic inequality and the affordability crisis have eroded confidence in government at all levels. DOI should look hard at where the process seems rigged against the interests of low-income and working-class New Yorkers.
A few examples:
The Rent Guidelines Board is responsible for setting rent increases for rent-stabilized apartments based, in part, on increases in landlord cost. For years, tenants have questioned the validity of this price increase data — which is self-reported — and have argued that the price index of operating costs (PIOC) is “one-sided.” DOI could use its full investigative powers — including subpoena power — to assess the PIOC’s validity as part of the debate over a rent freeze.
There is a 50 year history of fraud and corruption related to City leases for child care facilities. In 1976, City daycare leases were the subject of a grand jury investigation and were “one of the biggest giveaways in the history of the city.” A DOI investigation of current daycare center leases could detail how to minimize taxpayer cost and ensure that any move to universal childcare is protected from similar corruption.
Second, DOI should support effective government. While the agency should never hold back on investigations or audits finding fraud, waste and abuse, it should simultaneously speak with an equally loud, clear voice when government is working effectively and efficiently and, perhaps more importantly, when failures are due to policy decisions rather than malfeasance or misadministration.
For instance, cuts in federal SNAP funding will reduce the affordability of food for the roughly 1.8 million city residents who currently receive benefits every month. The Trump administration and congressional Republicans justified work requirements and a shift in administrative costs to states and local governments as ways to reduce or prevent fraud in the program. A DOI investigation could independently assess the fraud risk and determine the effect of SNAP cuts on New Yorkers’ access to needed benefits.
Third, DOI should put the public back into public integrity. This means connecting productively with ordinary New Yorkers to help identify and combat potential government malfeasance. The City Charter already requires DOI to “conduct annual outreach campaigns to educate the public on forms of government corruption, fraud, and waste, and provide information regarding how the public can submit complaints to the department.” This should be done with much more vigor and imagination.
The City of Chicago Inspector General, for example, uses community engagement as one of its key metrics, tracking participation in community events to “listen to community concerns, talk about our work, and even initiate intakes for complaints or suggestions to make city government better.”
And the New York City Comptroller, along with other audit agencies, has used public engagement as a means of both determining areas of focus and methodology for its audits.
Finally, DOI should focus more intensively on results. The true test of effective oversight is whether the work of the watchdog produces better government — less fraud, waste, abuse and corruption. The measure of effective oversight is not the number of audits or investigations, but the impact that those efforts have. Repeated investigations of an area of government may lead to multiple arrests and indictments. But if those investigations don’t also lead to programmatic reforms that prevent corruption and improve performance, oversight has not really succeeded.