On an October night in 2014, a Chicago police officer calmly radioed:
"Can someone get us a Taser? We're at 40th and Keeler. This guy, ah, kind of walking away, he has a knife in his hand."
Four minutes later, 17-year-old Laquan McDonald lay dying two blocks away, shot 16 times by an officer as the teenager held a knife and walked down the middle of the road.
Until this week, the public had seen only a silent video of Officer Jason Van Dyke shooting McDonald. On Wednesday, the city provided some of the sounds from that night, releasing redacted radio traffic between a dispatcher and officers at the scene.
Two officers had been trailing McDonald for nearly half a mile, from a trucking yard where he was allegedly breaking into vehicles and then through a Burger King parking lot. Officers called for a Taser as McDonald headed east on Pulaski Road.
"Anybody have a Taser?" the dispatcher called out. "Looking for a Taser; armed offender."
A minute and a half passes as the officers follow McDonald. "Walking towards Pulaski from Keeler, eastbound on 40th Street. Again, armed with knife," an officer says.
A minute later, the dispatcher repeats the call for a Taser. "Anybody close yet?" she asks. "Asking for a Taser for armed offender with a knife."
Within seconds, an officer radios: "Popped our tire on our car, squad." Police have said McDonald used his knife to slash the front tire of a squad car trying to block his path.
What follows is about a minute of other squad cars radioing that they are on their way to the scene. "Let me know when he's in custody, guys," the dispatcher says.
Eight seconds later, an officer yells out over his radio, "Shots fired by the police! It's shots fired by the police, squad. Get the ambulance over here."
"You guys OK?" the dispatcher asks.
"Ten-four, everything's fine," an officer radios back. "Roll the ambulance over here."
The teen was alive when paramedics arrived but died on the way to the hospital, authorities have said.
According to the video, Van Dyke and his partner arrived 10 minutes after the first call. Their weapons were drawn as they stepped from their Chevrolet Tahoe. Within six seconds of exiting the police car, Van Dyke opened fire. Fifteen seconds later, he had emptied his 16-round handgun, authorities said. His partner asked him to hold his fire as Van Dyke reloaded, authorities said.
Van Dyke was charged with first-degree murder last month hours before the city finally released the video.
The city also released a copy of a 911 call earlier that night reporting that McDonald was stealing radios from trucks in a parking lot.
"Hi, I need a cop over here on 41st and Kildare," the caller says. "I have a parking lot full of trucks, and I have a guy right here who stole the radios."
"Are you holding this person?" a dispatcher asks.
"Yeah, he's here," the caller says.
After asking for directions, the dispatcher says, "OK, we'll send the police. We will send the police."
McDonald fled the parking lot, and responding officers saw him walking with a knife, according to police.
In releasing the audio files, the city's Office of Emergency Management and Communications said it had redacted "private" portions of the radio traffic. That could include names, telephone numbers, home addresses and license plate numbers, the agency explained.
Crepeau and Wong are reporters for the Chicago Tribune.