CHICAGO (Reuters) - The new chief of the discredited watchdog agency that oversees Chicago’s 12,000-strong police force on Monday announced a shakeup aimed at improving investigations into police shootings, allegations of misconduct and use of excessive force.

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Sharon Fairley, a former federal prosecutor, was named acting head of the Independent Police Review Authority, or IPRA, after the former director was fired in December by Mayor Rahm Emanuel because of public outcry over police killings in the city. Emanuel in early December also fired the city’s police chief.

The agency was formed in 2007 to investigate problems at Chicago’s police force, which has a long history of complaints of abuse. IPRA has been plagued by budget and staffing shortages. It has been criticized for taking a long time to investigate police shootings and finding almost all of them justified.

Fairley said she hired a new chief of staff and chief investigator and was recruiting four lawyers to improve investigations.

She said she would increase IPRA’s contact with Chicagoans over the changes needed in the police department. However, she said she has been given no budget increase for the body.

Emanuel has faced calls for his resignation after the city released a video of a white police officer fatally shooting a black teenager in October 2014, one of a number of U.S. police killings that has sparked a national movement about policing and race.

In Chicago, prosecutors took more than a year to bring murder charges against police officer Jason Van Dyke in the fatal shooting of Laquan McDonald, who was shown in the video walking away from police while holding a knife. The furor over the shooting cast fresh attention on IPRA and police accountability issues.

Critics say IPRA has been too willing to accept police officers’ justifications for shootings. Fairley said she would change that.

Also on Monday, city attorney Jordan Marsh resigned after U.S. District Judge Edmond Chang ruled that Marsh had withheld evidence in a trial over a fatal police shooting and then lied about it, the Chicago Tribune reported. A spokesman for Chicago’s Law Department could not be reached for comment.

Chang ordered a new trial in reversing a federal jury’s decision in favor of Officers Raoul Mosqueda and Gildardo Sierra. The jury had concluded that they were justified in killing a black motorist during a 2011 traffic stop.