Former Detective David March, former Officer Joseph Walsh, and Officer Thomas Gaffney did not conspire to cover up the black teenager's death, Cook County Judge Domenica Stephenson found.
She said there was no evidence that the officers, who were previously charged with conspiracy, official misconduct and obstruction of justice, attempted to hide evidence related to McDonald's death, and even said that "the evidence shows just the opposite."
Stephenson said that the officers preserved the police dashcam video at the heart of the evidence that convicted white Officer Jason Van Dyke. Van Dyke was convicted of second-degree murder and aggravated battery in October after he shot McDonald, who was 17 years old in 2014, 16 times.
Prosecutors argued that March, Gaffney and Walsh, who was Van Dyke's partner, submitted false reports about what actually happened to try to prevent a criminal investigation into the shooting.
They also alleged that the officers falsely claimed that McDonald ignored verbal commands from Van Dyke, that Van Dyke shot McDonald after McDonald aggressively swung a knife at the officers and that he kept shooting the teen because McDonald was trying to get up still armed with the knife.
McDonald did have a small knife that he had used to puncture a tire on Gaffney’s police vehicle, but the dashcam video shows that he didn’t swing it at the officers before Van Dyke shot him and that he appeared to be incapacitated after falling to the ground.
“The case is clear, the case is straightforward, and it is concise,” Special Prosecutor Patricia Brown Holmes told the judge during her opening statements. “It boils down to what the defendants wrote on paper versus what is shown on video.”
McDonald's shooting death sparked large protests and led to major changes to Chicago’s policing, but only more than a year after the fact. City Hall only released the video to the public in November 2015 — 13 months after the shooting — because a judge ordered it to do so. The charges against Van Dyke weren’t announced until the day of the video’s release.
Van Dyke is scheduled to be sentenced on Friday.
The Associated Press contributed to this report.