Newly released videos taken at the scene of the shooting of a black teenager by a white Chicago patrolman could raise fresh questions about whether police properly documented the killing, as the city braced for more protests over the Thanksgiving weekend.
Like the first video released on Tuesday, the new footage inexplicably lacks discernible audio of the Oct. 20, 2014 shooting of 17-year-old Laquan McDonald by Officer Jason Van Dyke, according to the Chicago Tribune, which obtained the recordings.
As a result, the sounds of 16 gunshots that hit the teen, any commands shouted by police officers or other remarks are not available, the newspaper said late on Wednesday. The footage also does not show the actual shooting and offers few new visual details about the incident.
McDonald's killing and the 13-month delay releasing any video taken by dashboard cameras on squad cars at the scene have led to days of demonstrations in Chicago over police treatment of African-Americans and other minorities.
Activists say a culture of racial bias runs deep in the city's police department despite reform efforts.
The powerful Chicago Teachers Union on Thursday endorsed a "Black Friday" march organized by civil rights leader Reverend Jesse Jackson, to protest McDonald's shooting, and called for an independent investigation of what it described as a "cover-up."
"We have watched in anger and disappointment as the city has covered up police violence," CTU Vice President Jesse Sharkey said in a statement.
"Chicago's response to Laquan's death appears calculated to minimize political damage to the mayor, by removing this case from the election cycle," he said, referring to a gap between the shooting and the first-degree murder charge brought against Van Dyke on Tuesday.
Mayor Rahm Emanuel was re-elected to a second term in an April runoff after failing to win a majority in the February election. The CTU opposed a new term for the mayor because of his aggressive program of closing public schools to save money.
Protesters appeared to be waiting until the day after Thanksgiving, the so-called "Black Friday" that marks the traditional kickoff to the holiday shopping season, before returning to the streets. Just before marchers set off for the annual Thanksgiving Day parade on Thursday, there were no demonstrators in sight.
The first tape of the shooting was released under court order hours after Van Dyke was charged. It showed McDonald, who authorities said was carrying a pocket knife and had the hallucinogenic drug PCP in his system, as he was gunned down in the middle of a street.
Police said the sound was missing due to an unspecified technical problem.
According to the Tribune, the original tape contains the most complete visual record of the incident and was the only one in which the shooting was captured on camera. The newly released footage came from the dashboard cameras of five of the eight police squad cars present. The other patrol cars, including Van Dyke's, were positioned facing away from the action.
Excerpts from two of the new videos were posted on the newspaper's website.
The Tribune said no explanation has been given for why it was provided video for just five of the eight police vehicles at the scene.
According to the Tribune, the Chicago Police Department requires its officers to use in-car video if the vehicle is equipped with it.
Those video systems are supposed to automatically engage audio and video recording when the vehicle's emergency lights are activated. Officers may also manually engage the recording system without activating the lights, the newspaper said.
The footage obtained by the Tribune was furnished by the mayor's Law Department under an open-records request.
The original tape was made public a day earlier to the media at large under a court order, after an independent journalist had filed a Freedom of Information Act lawsuit. Police released that tape a day before the deadline, they said, after learning that a copy had been leaked to a local television station.