On November 24, 2015, police video that captured the shooting of Laquan McDonald in Chicago, Illinois was released to the public, almost 13 months after the incident took place. There has been a public outcry regarding not only the death of McDonald, but also the videos themselves.
The following blog post clarifies why there could be an absence of audio during the multiple videos released by the city of Chicago from the Laquan McDonald shooting.
Dash Camera Surveillance Systems Record Video and Audio
Video surveillance systems are closed circuit video recording systems that keep a pre-determined area under security by recording video and audio. Surveillance video cameras aid in deterring and documenting crime and other activity.
Some video surveillance systems record audio, others do not. Video surveillance systems in many department stores do not record audio. Video surveillance systems in gas stations, convenience stores and banks often do record audio, as well as video.
Police car dash cam surveillance systems record both audio and video for two reasons:
- To protect the police officer
- To deter profiling
Video Surveillance Systems like the ones used by the Chicago Police include Audio Recording
The question remains, why do the videos released by Chicago authorities of the Laquan McDonald shooting lack audio? What are the sounds heard on the video recordings that sound like sirens or whining?
If you watched the videos that have been released so far, electronic noise can be heard. This is defined as electronic cross talk. The digital video recorder in the squad car was recording audio, that is why we hear that whining sound. The problem is that no audio signal was being sent to the recorder. Was it a technical glitch or did the officers elect not to activate their body microphones? Perhaps they were all muted? Was there a problem downloading the digital recordings from each police car? Who has the chain of custody logs for the handling of this evidence?
In an interview for the Associated Press, our lead Audio Video Forensic Expert, Ed Primeau, comments on the lack of audio from multiple police cars being a red flag.
In a second interview for the Associated Press, published by ABC News, fellow Audio Video Forensic Expert Gregg Stuchman comments that “It’s plausible for a single squad car to have a glitch preventing sound recording.” How could multiple cars not have recorded audio?
“I’ve never heard of it before,” Stutchman said. “It raises a red flag. The more likely explanation is that audio was intentionally switched off.”
The reality of this situation is that a full forensic investigation needs to be performed by a neutral, independent Audio Video Forensic Expert in order to determine the reason for the absence of police dialogue and radio communication from the audio portion of the digital video recordings released in the Laquan McDonald shooting.
We have examined thousands of police dash cam systems here at Primeau Forensics. Some include audio, others do not. There are three methods of activating dash cam video and audio.
- The officer activates the recording manually
- The squad car reaches a certain, predetermined speed for recording to begin
- The video is engaged in record when the squad car flashers are activated
One important note; the officers have the ability to mute or not activate their body microphone transmitter should they decide. However, the in car microphone almost always remains on.
YouTube Fake Squad Car Video
The Associated Press asked Primeau Forensics to examine a YouTube video of the Laquan McDonald shooting that has audio. After careful forensic examination of the video, Ed Primeau concluded beyond a reasonable degree of scientific certainty that the audio track on the video is fake. Careful analysis of the audio spectrum contained on the video indicates many signs of post event alterations.
We hope this blog post about dash cam video and audio surveillance recordings will help clear up any misconception about the absence of audio on the Chicago Police Dash Camera Videos.