Story highlights Alvarez had come under intense criticism for her handling of the Laquan McDonald case

She conceded to Democratic challenger Kim Foxx

(CNN) Cook County State's Attorney Anita Alvarez conceded the Democratic nomination to challenger Kim Foxx on Tuesday, according to her campaign manager, Mike Carson.

But it was the Laquan McDonald case that proved her undoing.

Alvarez, who was first elected in 2008, had been seeking a third term.

McDonald, a black teenager, was shot and killed by a Chicago police officer in October 2014. Video of the shooting was released more than a year later, and only then, after a judge ordered it be made public under a reporter's Freedom of Information Act request.

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Shortly before the video was released, Alvarez announced charges against Jason Van Dyke, the officer who fired 16 shots at McDonald.

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