CHICAGO (CBSNewYork/CBS Chicago/AP) — The Rev. Al Sharpton is sounding off Tuesday after Chicago Mayor Rahm Emanuel fired the city’s police superintendent — a week after the release of a dash-cam video that showed a white officer fatally shooting a black teenager 16 times.

Emanuel called a news conference to announce the dismissal of Garry McCarthy, who only days ago insisted to reporters that the mayor had his “back.”

The mayor praised McCarthy’s leadership of the force but called it an “undeniable fact” that the public’s trust in the police had eroded.

“Now is the time for fresh eyes and new leadership,” Emanuel said.

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Protesters have been calling for McCarthy’s dismissal in response to the handling of the death of Laquan McDonald, a 17-year-old who was killed on Chicago’s Southwest Side in October 2014.

Emanuel and McCarthy have been under fire for the past week, with activists, protesters, religious leaders, and multiple elected officials – including the City Council Black Caucus, several Latino aldermen, and Cook County Board President Toni Preckwinkle – demanding McCarthy resign or be fired for his handling of the McDonald case, CBS Chicago reported.

Critics have also cited broader issues with the city’s crime rate and questions about department transparency in calling for McCarthy’s ouster.

WBBM-TV, CBS2 Chicago Chief Correspondent Jay Levine reported both the mayor and the superintendent had denied there was any problem in McCarthy’s leadership at all – until Tuesday. The mayor and the superintendent stood side by side just last week as the McDonald video was released.

“The mayor has made it very clear that he has my back, and if people peel away the onion on what’s happening right now in the policing world, you’re going to find a police department that’s doing an exceptional job,” McCarthy said just this past Friday. “And quite frankly, I’m not going to quit on the people of Chicago.”

But on Sunday, as demonstrations continued and calls for McCarthy’s ouster increased, the mayor and the superintendent began to face the facts about the future of the department.

On Tuesday, the Rev. Al Sharpton released a statement saluting McCarthy’s resignation, but said it was “a deposit on justice and not the full payment.”

“The Cook County State’s Attorney needs to step aside and use the model we have used in New York of forcing the governor to appoint a special prosecutor, not only for the case of Laquan McDonald but for all cases relating to the fatalities of citizens at the hands of police,” he said. “Governor Andrew Cuomo did it in New York and it should be a model for the rest of the country.”

In Chicago, the Rev. Michael Pfleger, who has been one of the loudest voices to call for McCarthy’s resignation, expressed similar sentiments.

“Removing McCarthy as the head of the department is not going to solve the core problem. This is a department that needs a total transformation,” Pfleger said. “We need a federal prosecutor that subpoenas everybody to find out who knew what and when; and anybody – anybody, from the top to the bottom – that knew hand helped this cover-up needs to go.”

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The city released video of the shooting only after a judge ordered it to be made public. The release set off several days of largely peaceful protests. Officer Jason Van Dyke has been charged with first-degree murder.

“Any case of excessive force or abuse of authority undermines the entire force and the trust we must build with every community in the city,” Mayor Emanuel said. Police officers are only effective “if they are trusted by all Chicagoans, whoever they are and wherever they live in the city.”

Emanuel introduced McCarthy as his pick to lead the department in May 2011, replacing former FBI agent Jody Weis.

Weis was appointed three years earlier by retired Mayor Richard M. Daley, following a 2007 scandal in which an off-duty officer, Anthony Abbate, was seen on video beating a female bartender after she refused to serve him more drinks. The fallout of that incident had led to the resignation of then-Supt. Philip Cline.

During his term, Weis proved unpopular with many rank-and-file officers who claimed Weis did not stand behind them. He left his post a couple of months before Emanuel took over as mayor and appointed McCarthy.

Following McCarthy’s dismissal, Ald. Howard Brookins Jr. (21st), a member of the Black Caucus, said he appreciated Emanuel’s “willingness to change course.”

Emanuel, who also announced a newly created task force on police accountability, said Chief of Detectives John Escalante will oversee the Police Department until a permanent replacement is named.

The mayor said he wants the next chief to safeguard public safety and restore trust between the community and the police.

McCarthy rose through the ranks of the NYPD and was police director in Newark, New Jersey, when he was hired in Chicago. He promised he would “have the cops’ backs.”

At the time, Emanuel praised him for knowing how to run a large police force and said the city needed “a leader with Garry’s depth of experience and a track record for delivering results.”

In New York, McCarthy rose from patrolman to an executive position and was involved in rescue and recovery efforts after the Sept. 11 terrorist attacks before taking the job in New Jersey. But his time in Newark was not without challenges or complaints.

The NAACP in New Jersey said McCarthy was more concerned about improving the safety of downtown Newark than of its neighborhoods. The American Civil Liberties Union complained that Newark police were plagued with problems from lax internal oversight to issues of excessive force during arrests.

As CBS News’ Adriana Diaz reported, the mayor also announced a new police accountability task force.

Chicago native and former Massachusetts Governor Deval Patrick will serve as senior adviser. Patrick had also served as head of the Department of Justice’s Civil Rights Division.

Outside of Emanuel’s office, community leaders called for more independent oversight.

“The mayor calling for a special task force is kind of like the fox watching the hen house,” one said.

Emanuel said he takes responsibility for how the case was handled, and called his latest action, “a work in progress.”

The silent Chicago video shows McDonald walking down the middle of a four-lane street. He appears to veer away from two officers as they emerge from a vehicle, drawing their guns. Van Dyke opens fire from close range and continues firing after McDonald crumples to the ground.

Police have said McDonald was carrying a knife, and an autopsy revealed that he had PCP, a hallucinogenic drug, in his system. Cook County State’s Attorney Anita Alvarez has said the 3-inch blade recovered from the scene had been folded into the handle.

Defense attorney Dan Herbert says his client feared for his life, acted lawfully and that the video does not tell the whole story.

Van Dyke was released from jail Monday after paying the $150,000 required of his $1.5 million bail.

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