By Dakin Andone and Steve Almasy

CNN

(CNN) -- Three current or former Chicago police officers were indicted Tuesday on state felony charges of conspiracy in the investigation of the 2014 shooting death of Laquan McDonald.

Former Detective David March, and former Patrol Officer Joseph Walsh and Patrol Officer Thomas Gaffney were charged with conspiracy, official misconduct and obstruction of justice, according to a news release from Special Prosecutor Patricia Brown Holmes' office.

"The indictment makes clear that these defendants did more than merely obey an unofficial 'code of silence,' rather it alleges that they lied about what occurred to prevent independent criminal investigators from learning the truth," Holmes said.

McDonald, 17, was killed in October 2014 when Chicago police officer Jason Van Dyke shot him 16 times. Van Dyke has pleaded not guilty to six counts of first-degree murder and 16 counts of aggravated battery with a firearm, with the latter charges apparently corresponding to each shot he fired at McDonald.

He is suspended without pay.

Video released after legal battle

Dashcam video of the shooting -- released in November 2015 after a court battle -- contradicted nearly everything police said happened the night McDonald died. It showed McDonald walking away from police as he held a 4-inch knife, not lunging toward officers, as police had said. The shooting led to calls for reforms and fueled a national conversation about police use of deadly force.

"The shooting of Laquan McDonald forever changed the Chicago Police Department and I am committed to implementing policies and training to prevent an incident like this from happening again," police Superintendent Eddie Johnson said. "We will also continue to implement meaningful reforms that build community trust, provide greater training and resources to our dedicated officers, and make Chicago safer."

In the 11-page indictment Van Dyke is referred to as Individual A and as a part of the conspiracy. He has been accused of official misconduct.

Arraignment set for July

Gaffney, 43; March, 58; and Walsh, 48, are accused of writing incident reports that "contained important false information in an attempt to prevent or shape any criminal investigation."

Several reports referred to three officers being battered, which the the indictment says is false. Police statements that McDonald was threatening Van Dyke with his knife were also lies, the document says.

The indictment also says the officers failed to interview at least three witnesses whose versions of the events were different than those of police.

The conspiracy was carried out through "various means of communications," the indictment says.

The officers will be arraigned July 10. It is unclear whether they have attorneys. CNN's attempts to reach the officers were not immediately successful.

The three charges each carry penalties of three to five years in prison and possible fines up to $25,000.

March was a police officer for more than 30 years, authorities said. Walsh, who was Van Dyke's partner, was with the department for about 20 years.

Gaffney, who is suspended without pay, has also been with CPD for two decades.

The indictment says there are other individuals that may be part of the conspiracy, but Holmes wouldn't comment on whether other officers will be indicted. She told reporters the investigation is ongoing.

The Chicago Police Board, the independent civilian body that oversees the department, told CNN it has no statement.

CNN's Laura Jarrett and Brad Parks contributed to this report.