A former federal prosecutor will head the agency charged with investigating police shootings in Chicago after the immediate resignation of its chief administrator, Mayor Rahm Emanuel’s office announced Sunday.

Sharon Fairley will take over for Scott Ando as the head of the Independent Police Review Authority, according to a statement from the mayor’s office. Fairley declined to comment when reached Sunday by the Chicago Sun-Times. Ando could not be reached.

“Scott has taken important steps to move IPRA forward and reduce its backlog of cases,” Emanuel said in a statement. “Yet it has become clear that new leadership is required as we rededicate ourselves to dramatically improving our system of police accountability and rebuilding trust in that process.”

Emanuel made his announcement hours after hundreds of protesters led by the Rev. Jesse Jackson marched through the Loop on Sunday, demanding accountability after the release of video footage of Chicago Police Officer Jason Van Dyke fatally shooting 17-year-old Laquan McDonald 16 times on Oct. 20, 2014.

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The release of that video has led to calls for Emanuel and Cook County State’s Attorney Anita Alvarez to resign. In response, the mayor has expanded the police body camera program; fired Chicago Police Supt. Garry McCarthy; and formed a task force to review police discipline.

Meanwhile, U.S. Attorney General Loretta Lynch is expected to launch a Civil Rights Division investigation of the Chicago Police Department.

City Hall has also promised to release further police videos, such as one that reportedly captured Chicago Police Officer George Hernandez shooting 25-year-old Ronald Johnson III in the back as he ran from police.

But lawyers also want a federal judge to allow the release of surveillance video that caught the death of Cedrick Chatman in January 2013.

Lorenzo Davis, a former Chicago police commander and top IPRA investigator, has claimed he was fired this year for resisting Ando’s orders to justify police shootings.

Davis’ lawyer told the Sun-Times last week that Chatman’s shooting was the video that led to Davis’ ouster.

Davis himself called Chatman’s death a “murder” — one that was officially justified in an IPRA report.

Fairley, IPRA’s new leader, joined Chicago’s Office of Inspector General as its first deputy inspector general and general counsel this year after serving for eight years as a prosecutor in the U.S. Attorney’s Office in Chicago. There she prosecuted financial and government program fraud, national security, immigration, narcotics and violent crimes cases.

“I am honored to have the opportunity to continue to serve the City of Chicago at this important juncture and look forward to this new challenge,” Fairley said in a statement distributed by Emanuel’s office. “The mission of IPRA is critically important, and the investigative work must be conducted with the integrity, transparency, and expeditiousness that both the officers and the citizens we serve deserve.”

Contributing: Fran Spielman