- Video: Teen gunned down while riding scooter
- More: Most Popular stories, videos and more
- More: Get breaking news alerts
Witnesses said they saw Alvarado riding a scooter down the sidewalk before a black SUV pulled up next to him.
"I see like a crowd of people, and he's right there laying there, like trying to breathe, and people are trying to help him out, and the cops came, probably like 20 minutes later," said one resident who did not want to be identified.
Alvarado was pronounced dead at the scene.
A small memorial has been set up at the place where Alvarado was killed.
Authorities are not calling the crime a gang killing yet, but neighbors say they are convinced what happened was a result of gang activity that plagues the neighborhood.
Police do not believe Alvarado was involved in gangs.
As detectives comb the scene for clues, local residents are also trying to figure out what happened.
Resident Ivan Godinez said he heard the shots.
"We heard fireworks earlier," he said. "We came outside, we heard shots right here, we thought it was more fireworks, and next thing we know there was a van parked right here, and we didn't know there was a body behind the van."
Godinez said he used to be in a gang, but now he tries his best to warn others of the dangers that kind of life can bring with it.
"I'm 44, I'm retired out of gang banging. I try to give advice instead of making them worse. But they're on their own little mission, you know, trying to get little stripes here and there, but I don't think it's worth it. It's not worth it," he said.
Authorities are urging anyone with information about the shooting to call the L.A. County Sheriff's homicide detectives at (323) 890-5500.