The driver of a black Chevy van slammed into a bus stop across the street from South Gate Middle School at Firestone Boulevard and Otis Street at about 3:30 p.m.
Police do not believe the driver was under the influence of drugs or alcohol, and said the crash may be a result of a mechanical failure.
"It was a black van, and they were going really fast," said student Clarissa Alvarez.
The driver hit three 13-year-old boys, a 14-year-old girl and a 14-year-old boy. The 14-year-old boy died from his injures at St. Francis Hospital in Lynwood.
Officers have been questioning the driver, and say he has been cooperative. The driver has not been charged.
"He said he tried to basically do a power swing into this McDonald's driveway here, and wasn't able to do so. Instead he hit the curb, and jumped the curb, hit the electrical box, and then slammed into the bus stop," said Capt. Vincent Avila from the South Gate Police Department.
Police said they are interviewing about 25 witnesses and also reviewing a McDonald's surveillance camera that reportedly caught the whole thing on tape.
Police are looking for the passenger of the van, who apparently jumped out of the van and fled while the driver was knocked out.
Students on Tuesday were mourning the loss of a friend as the investigation continues.
"No one knows what actually happened to the man, if the brakes didn't work or something. He probably lost control," said one student.
Anyone with information is urged to call the South Gate Police Department at (323)563-5400.
- Get more local news headlines from Los Angeles
- Have a news tip? Send your tips, video, or pictures