In the days following the fatal shooting of 17-year-old Laquan McDonald, it is alleged that officers did everything they could to cover up any Officer Jason Van Dyke's wrongdoings.
Prosecutors say the officers gave false statements that McDonald assaulted them and gave misleading descriptions of the shootings; ignoring witnesses who saw the events differently.
The dash cam video released by the Chicago Police Department shows Van Dyke shooting McDonald 16 times.
This lead to an investigation by the US Justice Department, which revealed documented years of systemic civil rights violations.
There were several accounts of officers' shooting at fleeing suspects, using force as retaliation and purposely botching probes into fellow officers' misconduct.
This probe is also what led to the indictment of Detective David March and Officers Joseph Walsh and Thomas Gaffney.
The three are accused of being the leaders of the conspiracy to cover up for Van Dyke.
A department spokesperson says March and Walsh have resigned and Gaffney has been suspended without pay.