Chicago Mayor Rahm Emanuel answers questions during a news conference Friday, Jan. 13, 2017, in Chicago. The U.S. Justice Department issued a scathing report on civil rights abuses by Chicago's police department over the years. The report released Friday alleges that institutional Chicago Police Department problems have led to serious civil rights violations, including racial bias and a tendency to use excessive force. (AP Photo/Teresa Crawford)
Chicago Mayor Rahm Emanuel answers questions during a news conference Friday, Jan. 13, 2017, in Chicago. The U.S. Justice Department issued a scathing report on civil rights abuses by Chicago's police department over the years. The report released Friday alleges that institutional Chicago Police Department problems have led to serious civil rights violations, including racial bias and a tendency to use excessive force. (AP Photo/Teresa Crawford) Credit: Teresa Crawford

Chicago — A federal investigation into the Chicago police found that the department routinely uses excessive force and violates the constitutional rights of residents, particularly those who are black and Latino.

The blistering 164-page report by the Justice Department, released on Friday, put an unwelcome spotlight on Chicago, a city already struggling with a surge in gun violence that has pushed homicide numbers to their highest level in two decades.

The report and a pledge by city officials to reform the police department come in the last days of President Obama’s administration, which has aggressively pursued investigations of abuse by local law enforcement.

On Friday, Chicago leaders said they had promised to negotiate with the federal government an order, enforceable by a judge, that would overhaul how the police department handles training, accountability and the way officers use force. A similar agreement is in place for the city of Baltimore.

But President-elect Donald Trump’s nominee for attorney general, Sen. Jeff Sessions, R-Ala., has criticized government lawsuits that force police reforms. Trump himself has been a staunch defender of police officers, who he has called the “most mistreated people in this country,” and he has said that crime in this country is on the rise and requires a forceful response.

When asked whether the Chicago action would retain its strength under a Trump administration, Attorney General Loretta Lynch said Friday she expected the agreement with Chicago to live on beyond Obama’s term.

“Yes, the top people at the Department of Justice move on, but this agreement is not dependent on one, or two, or three people,” she said.

The report details a grim succession of anecdotes.

Officers are described as running after people who they had no reason to believe committed serious crimes. Some of those chases ended in fatal gunfire.

In one case, officers began chasing a man who was described as “fidgeting with his waistband.” Police fired a total of 45 rounds at him, hitting and killing him. The officers claimed the man fired at them during the chase, though no gun was found on the man, the report states, and a gun found almost a block away was both “fully-loaded and inoperable.”

These anecdotes were not limited to fatal incidents. A 16-year-old girl is described as being struck with a baton and shocked with a stun gun for not leaving school when she was found carrying a cellphone. A 12-year-old Latino boy was “forcibly handcuffed” without explanation while riding his bike near his father.

Federal officials were also told about officers taking young people to the neighborhood of a rival gang to either leave them there “or display the youth,” putting their lives in danger by suggesting they had given information to police.

While the federal officials on Friday noted that city officials have made efforts recently to enact reforms, they said “complicated and entrenched” causes of the problems could be fixed only with outside help.

The report is the culmination of a 13-month investigation into the country’s second-biggest local law enforcement agency, which has a grim history that includes a former police commander who spent decades leading a torture ring until he was suspended and then fired in the early 1990s.

The probe was launched in December 2015 soon after video footage emerged of a white Chicago police officer fatally shooting a black teenager. Protests in the city soon followed.

At a news conference on Friday, Chicago Police Superintendent Eddie Johnson said “some of the findings in the report are difficult to read.” But he also said that many of the problems had already been identified and officials were working to correct them.

“Quite simply, as a department, we need to do better, and you have my promise and commitment that we will do better,” Johnson said.

Officers are described as lying, both as part of a “code of silence” but also in cases in which they had little reason to lie, the report states.

But investigators also described an utter absence of morale in the police force, as officers increasingly feel they are adrift and unsupported, and the report describes suicides and suicide threats among officers as “a significant problem.”

Many “officers feel abandoned by the public and often by their own department,” the report states. “We found profoundly low morale nearly every place we went within CPD. Officers generally feel that they are insufficiently trained and supported to do their work effectively.”

Dean Angelo Sr., president of the Chicago Fraternal Order of Police, did not respond to a message seeking comment Friday.

Distrust remains an issue between police officers and residents in Chicago. In a poll taken last year, 1 in 3 residents said the city’s police officers were doing an excellent or good job; far fewer black residents (12 percent) felt that way than white residents (47 percent) or Hispanic residents (37 percent). The new report also states that police use force almost 10 times as often against black people as white people. Complaints filed against officers by white people were substantially likelier to be substantiated than those filed by black people or Latinos.

Federal investigators said their inquiry found that the Chicago police force did not provide officers with suitable guidance for using force, investigate improper uses of force or hold officers accountable for such incidents. Investigators also faulted the city’s methods of handling officer discipline, saying the process “lacks integrity,” while saying that in the rare case in which misconduct complaints are sustained, discipline is “haphazard and unpredictable.”

Training is repeatedly described as woefully inadequate, with the report describing officers in a class on deadly force being shown a video made more than three decades ago that depicted tactics “clearly out of date.”

Democratic Mayor Rahm Emanuel acknowledged on Friday that there were questions surrounding what the next administration would do but vowed to continue working with the government.

“We will continue on the path of reform, because that is the path of progress,” he said.