(CHICAGO) Citizens have to give a sworn affidavit when they file complaints against Chicago Police officers — a requirement that creates a “tremendous disincentive to come forward with legitimate claims,” according to the Department of Justice.

In a sweeping report released Friday about the use of excessive force by Chicago Police officers, the DOJ said about half of the complaints filed against cops are dropped because of a lack of an affidavit, the Chicago Sun-Times is reporting.

And those agencies that investigate police misconduct — the Independent Police Review Authority and the police department’s Bureau of Internal Affairs — rarely use an override system that lets them look into a complaint without a citizen’s affidavit, DOJ added.

“IPRA and BIA should be acting more aggressively to ensure that this requirement does not stand in the way of investigating meritorious, and sometimes egregious, allegations of misconduct,” the report said.

The DOJ findings echoed another report unveiled in April 2016 by Mayor Rahm Emanuel’s hand-picked Police Accountability Task Force, which noted that IPRA had closed about 618 complaints per year since 2011 for a lack of an affidavit, about 40 percent of the total. Internal Affairs closed about 537 complaints per year for the same reason.

The heads of IPRA and Internal Affairs rarely seek overrides of the sworn affidavit requirement and “not to the extent it could and should be” done, the task force found.

Investigators for IPRA and Internal Affairs aren’t very active in trying to get citizens to sign the affidavits, according to the mayor’s task force.

“Investigators used to actively seek out the affidavits, sometimes even knocking on doors. Investigators now play a much more passive role and have placed the burden on the complainant,” the task force said in April.

The DOJ report, which found a “pattern and practice” of the use of excessive force by Chicago Police officers, elaborated on the issue of sworn affidavits, which the city started requiring in 2004 because of a change in state law and department policy.

The Fraternal Order of Police had pushed for the law to cut down on frivolous complaints. FOP officials predicted fewer people would file false allegations under the threat of perjury. Over the next year, excessive force complaints against cops fell more than 25 percent.

DOJ said there are many reasons why someone wouldn’t want to file a sworn affidavit.

“Chicago residents who have lost faith in police accountability altogether have no interest in participating in that very system,” the DOJ report said. “Others fear retaliation — if they proceed with an investigation, they will be targeted by CPD officers.”

Others who are criminal defendants or who have sued the police often follow their lawyers’ “reasonable advice and refrain from providing verified statements pending their criminal and civil litigation,” the report said, adding that investigators rarely go into Cook County Jail or prisons to get affidavits from people behind bars.

“For most of the lawsuits in which police misconduct victims received significant settlements or verdicts, IPRA’s parallel misconduct investigation was closed for lack of an affidavit,” the DOJ report said.

An appendix to the Chicago Fraternal Order of Police contract with the city allows for the heads of IPRA and Internal Affairs to seek an override of the requirement to have a sworn affidavit by a citizen.

If they review “objective verifiable evidence” such as arrest reports, videos or witness statements, and they believe it’s necessary for a probe to go forward, they can seek approval for an override from the head of the other investigative agency, IPRA or Internal Affairs. For instance, IPRA’s administrator must go to the head of the police department’s Bureau of Internal Affairs for approval of an override.

But when DOJ officials interviewed IPRA’s investigators, they were told that overrides weren’t encouraged and no training was provided on how to get one.

“Not surprisingly, this override provision was only used 17 times in the last five years,” the DOJ report said.

DOJ said IPRA and Internal Affairs should start interviewing witnesses and canvassing for information immediately — even without an affidavit — to show they’re “not indifferent to complaints of police misconduct.”

Mia Sissac, a spokeswoman for IPRA, said its administrator, Sharon Fairley, is now seeking overrides whenever possible. Eleven of them were done in 2016, more than in any prior year, she said.

Still, that was a small fraction of the 205 cases that IPRA closed for a lack of a sworn affidavit in 2016. Dean Angelo, president of the Chicago FOP, said he’s been saying all along that the police contract doesn’t impede investigations of police misconduct — it’s the investigating agencies that are the problem.

“We’ve been pointed to as the big problem in this process,” Angelo said. “The contract isn’t the problem. It’s the lack of the investigations being timely. It’s the lack of [investigators] taking statements. Now you have another agency [DOJ] saying it’s not the contract, it’s the investigation that’s the problem.”

IPRA will be reconstituted as the Civilian Office of Police Accountability later this year, with more employees and a bigger budget, according to the Emanuel administration.