Chicago's mayor fired the city's police chief Tuesday, a week after the release of a dash-cam video that showed a white officer fatally shooting a black teenager 16 times.Mayor Rahm Emanuel called a news conference to announce the dismissal of Superintendent Garry McCarthy, who only days ago insisted to reporters that the mayor had his "back."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 in October 2014.It is the latest fallout from police killings in the U.S. A number of deaths of African-Americans at the hands of law enforcement have given rise to the "Black Lives Matter" protest movement.The mayor praised McCarthy's leadership of the force but called it an "undeniable fact" that the public's trust in the police has eroded."Now is the time for fresh eyes and leadership," Emanuel said.The city released police 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.McCarthy has been chief since May 2011.The audio-free 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 (8-centimeter) 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.Emanuel introduced McCarthy as his pick to lead the department in May 2011, replacing former FBI agent Jody Weis, who was unpopular with many rank-and-file officers who claimed Weis did not stand behind them.McCarthy rose through the ranks of New York City's police department and was police director in Newark, New Jersey, when he was hired in Chicago. At the time he promised he would "have the cops' backs."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 civil rights organization 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.