CHICAGO — Three Chicago police officers were acquitted Thursday of charges they had conspired and lied to protect a white police officer who fired 16 deadly shots into a black teenager, a contentious verdict in a case over what many viewed as a “code of silence” in the Police Department.

The judgment was delivered by a judge and not a jury. Associate Judge Domenica Stephenson rejected the prosecutors’ arguments the officers had shooed away witnesses and then created a narrative to justify the 2014 shooting, which prompted citywide protests, the firing of the police chief and a wide-ranging federal investigation into the police force.

The ruling came more than three months after Officer Jason Van Dyke was convicted in October of the second-degree murder of Laquan McDonald, and on the afternoon before he was scheduled to be sentenced for a killing that was captured on an infamous police dashboard camera video.

The three police officers — David March, Joseph Walsh and Thomas Gaffney — contradicted what the video showed. In it, Van Dyke fires repeatedly at McDonald, who is wielding a knife, as he moves slightly away from the officers and even as he lies crumpled on the ground. Prosecutors cited that footage repeatedly as they built a case against the officers, who are white, on charges of conspiracy, official misconduct and obstruction of justice.

Stephenson said that even though the officers’ accounts of the shooting differed from the videos, that did not amount to proof that they were lying. “Two people with two different vantage points can witness the same event,” she said, and still describe it differently.

The officers, who were brought to trial in November, were accused of writing in official reports that McDonald had tried to stab three other officers, saying they saw him trying to get up from the ground even after a barrage of shots.

Walsh, who was Van Dyke’s partner on the night of the shooting and who has resigned from the department, said little. The experience has been “heartbreaking for my family,” he said. “A year and a half.”

But many others were outraged.

“The verdict says to police officers that you can lie, cheat, steal, rape, rob and pillage, and it’s OK,” said the Rev. Marvin Hunter, who is McDonald’s great-uncle.

This article originally appeared in The New York Times.