Chicago Mayor Rahm Emanuel speaks to the media Thursday in Chicago. (M. Spencer Green/AP)

This story has been updated to reflect that President Obama did not speak with Mayor Rahm Emanuel after the Laquan McDonald video was released.

Rahm Emanuel may have thought the worst was over in April, when he won election to a second term as Chicago mayor, after a bruising campaign and a forced runoff with Jesús "Chuy" García, a little-known county commissioner who accused him of catering to special interests and failing to do enough to fight crime.

But then came a judge’s order to release a police video of a white Chicago police officer shooting 17-year-old Laquan McDonald 16 times in October 2014.

Over the past two weeks, prosecutors charged the officer with murder and Emanuel fired his police chief, Garry F. McCarthy, acknowledging that significant segments of the city have lost trust in the force. Emanuel continues to face questions about the city’s delay in releasing the video as he labors anew to persuade voters, particularly in the city’s black neighborhoods, that he understands their fear and frustration.

“People are angry,” said Chicago Alderman Jason C. Ervin, who thinks Emanuel and his staff “need to be more collaborative, working with the community. There’s definitely some fence-mending that needs to be done if his long-term goal is to stay where he is.”

For Emanuel, 56, a consummate tactician who skillfully navigated the Washington labyrinth in Congress and the White House as a senior adviser to President Clinton and as President Obama’s chief of staff, this could be the toughest test of his political skills. The U.S. attorney’s office is investigating the Chicago police and the Justice Department is considering a request to open a civil rights investigation.

In appealing for the inquiry, Illinois Attorney General Lisa M. Madigan (D) asserted that “trust in the Chicago Police Department is broken.” Democratic presidential candidate Hillary Clinton said Wednesday she, too, wants a Justice Department inquiry, as have other prominent Democrats including Senate Minority Whip Richard J. Durbin of Illinois. In an interview, Durbin said on Thursday he “hand-delivered a letter to the attorney general today asking for the investigation of the incident and police department of Chicago,” and he said he hoped that Attorney General Loretta E. Lynch would announce one shortly.

After casting doubt earlier this week on the value of an additional outside investigation, Emanuel said Thursday that the city “welcomes” a Justice Department role in examining “systemic issues” in the police department. He said he is “open to anything that will help give us answers and restore the trust that is critical to our public safety efforts.”

Also on Thursday, Emanuel said he would no longer fight the release of another dash-cam police video. The family of Ronald Johnson III, who was fatally shot in the back by an officer eight days before McDonald, has been trying to get the video released for more than a year. Emanuel told reporters that his office would stop opposing the video’s release next week.

Emanuel’s immediate challenges in the nation’s third-largest city stretch beyond issues of crime and policing. The city is seeking hundreds of millions of dollars from a state legislature that has been unable to pass a budget for months. The Chicago Teachers Union, a major Emanuel foe, has scheduled a strike vote for next week, slightly more than three years since teachers walked off the job. To top it off, “Chi-Raq,” a movie about Chicago violence directed by Spike Lee, opens in the city this week.

Emanuel has made no secret of his frustration with the movie’s title, which echoes the bloody, factional fighting in Iraq. In recent days, he has sought to regain the initiative by pledging further police reform and trying to connect with skeptical Chicagoans.

“I know who I am, and I know what my flaws are, what my shortcomings are, and what my intents are. Sometimes I’m good at executing on that and being consistent, and sometimes I’m not,” Emanuel said in a sometimes-testy exchange with reporters this week.

This is a “raw time,” said Democratic strategist David Axelrod, a longtime Emanuel ally who served with him in the Obama White House. Axelrod said in an e-mail that the mayor “has to contend with the suggestion — unfounded, I think — that the city sat on the release of the tape until after his election. But he also has the opportunity to make some historic reforms that will make a real difference.”

Axelrod noted that although use of excessive police force is not new to Chicago — he wrote his first newspaper column 43 years ago on that exact subject, “You fit it with other tragedies we’ve seen nationally, and it’s a seismic event.”

President Obama, who worked on issues of policing as an Illinois legislator, has watched the video of the McDonald shooting. A White House official, who requested anonymity to discuss a private conversation, said the president had not spoken with Emanuel in the days since its release. On Wednesday, White House press secretary Josh Earnest told reporters that the mayor has confronted the challenges “quite directly.”

“We’re in a place where the usual solutions are not going to be enough,” said Alderman William D. Burns, whose district includes Hyde Park, on Chicago’s South Side. “There’s not just the policy work. There needs to be a signal — and I think he’s trying to do this — that this is not going to be business as usual.”

In the October 2014 video recorded by a police dashboard camera, McDonald is seen walking down a street. Officer Jason Van Dyke opens fire from a distance, and the teenager falls to the ground as bullets continue to pierce his body. Emanuel, who resisted release of the video for 13 months, said he did not take an early look.

A judge last month ordered the city to make the video public. On Nov. 24, Cook County prosecutors charged Van Dyke with first-degree murder, and Emanuel released the video a few hours later.

Protests followed, with the ire focused on police department practices at a time of heightened national attention on the use of deadly force by officers. Some of that attention has turned to Emanuel.

“Hey, hey! Ho, ho! Rahm Emanuel’s got to go!” some protesters chanted, three days after the video’s release, on Black Friday, as they marched down Michigan Avenue in the heart of Chicago’s downtown shopping district. Others, reacting to the gap between the Van Dyke shooting and the video’s release, shouted, “Stop the coverup!”

Emanuel — who abruptly fired McCarthy, the Chicago police chief, on Tuesday after strongly backing him a few days earlier — is in no danger of a recall, and the next mayoral election is not until 2019. But politicians and ordinary voters alike are calling on Emanuel to remake a police department whose history of brutality is made plain by court documents and payouts to victims and their families.

A 2014 examination by the nonpartisan Better Government Association found that the city had spent more than $500 million in the previous decade on police-related court judgments, settlements and legal fees. In May, the city council voted to pay $5.5 million to victims tortured or abused in ’70s and ’80s by the notorious police unit known as the “Midnight Crew,” directed by then-Cmdr. Jon Burge.

After struggling to persuade voters that he understands the pain and fear of life in many Chicago neighborhoods, Emanuel said he meets with families of young victims in a city that has recorded more than 400 homicides and more than 2,700 shootings this year. He also described unpublicized community conversations that he conducts for constituents to “know that I’m listening to what they have to say.”

Emanuel also made clear that he has not considered resigning.

“We have a process,” he said. “It’s called an election.”

Eilperin reported from Washington.