A coalition of elected leaders, activists and attorneys filed a petition asking that a special prosecutor be appointed to take over the case of Laquan McDonald’s killing.

The coalition is also calling for the city to investigate whether Chicago police lied about what took place at the scene of the shooting. According to the petition, a political alliance between Cook County State’s Attorney Anita Alvarez and the police union creates a conflict of interest for Alvarez and should disqualify her from prosecuting Officer Jason Van Dyke for killing McDonald.

Alvarez is in the midst of a tough re-election fight. Critics have called for her resignation since she charged Van Dyke with McDonald’s murder just hours before a judge forced the city to release the disturbing video of the teen’s killing.

Read more at Chicago Tribune.