Why are so many police dashcam videos silent?

Chicago Police Department officers stashed microphones in their squad car glove boxes. They pulled out batteries. Microphone antennas got busted or went missing. And sometimes, dashcam systems didn’t have any microphones at all, DNAinfo Chicago has learned.

Police officials last month blamed the absence of audio in 80 percent of dashcam videos on officer error and “intentional destruction.”

A DNAinfo Chicago review of more than 1,800 police maintenance logs sheds light on the no-sound syndrome plaguing Police Department videos — including its most notorious dashcam case.

Maintenance records of the squad car used by Jason Van Dyke, who shot and killed Laquan McDonald , and his partner, Joseph Walsh, show monthslong delays for two dashcam repairs, including a long wait to fix “intentional damage.”

On June 17, 2014, police technicians reported fixing a dashcam wiring issue in police vehicle No. 6412, the squad shared by Van Dyke and Walsh, about three months after it was reported broken, records show.

A day later, the same vehicle’s dashcam system was reported busted again. It took until Oct. 8, 2014, to complete repairs of what technicians deemed “intentional damage,” according to reports.

Just 12 days later, on Oct. 20, 2014, dashcam video recorded from squad car No. 6412 on the night Van Dyke shot and killed McDonald did not record audio. The video that went viral showing Van Dyke killing Laquan was taken from a different squad car, but it, too, had no audio.

And on Nov. 21, 2014, a review of 10 videos downloaded from Van Dyke’s squad car dashcam determined it was “apparent … that personnel have failed to sync the MICs [sic],” police records show . . .

Four other police vehicles at Laquan’s shooting scene that had dashcam systems also failed to record audio. Only two of the five vehicles had dashcams that actually captured video.

The dashcam in police vehicle No. 8489, shared by officers Thomas Gaffney and Joseph McElligott the night of Laquan’s shooting, recorded 37 “event videos” in October 2014, and had an operational dashcam the night of the shooting. But “due to disk error” no video was recorded at the shooting scene, according to police reports.