Beck said officers with the LAPD's Hollenbeck Division spotted the vehicle in Boyle Heights on Saturday night, hours after it had been reported stolen and a description broadcast to officers in the area.
The officers followed the vehicle briefly until it pulled over, Beck said. When the officers approached the vehicle, the chief said, the sole occupant inside "armed himself with a sawed-off shotgun," resulting in the shooting.
The teenager -- identified by coroner's officials as Jose Mendez -- was pronounced dead at the scene.
Beck said Mendez was close to the officers but said he did not know whether the teen pointed the gun at police. The chief said he expected to learn more about the deadly encounter during an "in-depth briefing" in the coming days.
The chief's comments came amid a heated Police Commission meeting, where dozens of activists criticized the board's decision last week to clear the officers who fatally shot a homeless man on skid row.
The March 1, 2015, shooting of Charly Leundeu Keunang -- a 43-year-old Cameroonian native known as "Africa" on skid row -- became a rallying cry for LAPD critics in recent months. His death reignited complaints that police use heavy-handed tactics on skid row residents, a population plagued by mental illness and drug use.
Although the Police Commission faulted a rookie officer's tactics leading up to the deadly encounter, the panel determined the officers and sergeant who opened fire acted within department policy.
Recordings from body cameras worn by some of the officers showed Keunang's hand grabbing the rookie officer's holstered pistol in the moments before the shooting, according to reports from Beck and the commission's inspector general made public last week.
On Tuesday, activists booed the Police Commission's president as he entered the room and turned their backs on Beck when he spoke. They frequently interrupted the meeting by shouting Keunang's name.
"Can't kill Africa," they chanted. "Can't kill Africa."
At one point, some activists left their seats and stood at the front of the room, holding American flags upside down and wearing ropes around their necks.
At least a dozen people were asked to leave the meeting and escorted by police out of the room. One man was arrested on suspicion of battery on a police officer, an LAPD spokesman said.
The Department of Justice announced Tuesday that Atty. Gen. Loretta Lynch would stop by Los Angeles as part of a six-city tour focused on police-community relations. Beck told the Police Commission that he expects the attorney general to visit in June.
Beck said he planned to talk to Lynch about the “evolution” of LAPD’s community policing efforts and the strides his department has made. The LAPD has spent years repairing the relationships between police and residents that were once so fraught they led to riots.
“Obviously this has been a tough year, nationally, for communities and their belief in police departments,” Beck said. “Even though we have issues here, I believe we have weathered that because we are so diligent at developing relationships. I hope to share that with the attorney general.”
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