Los Angeles Fire responded to the incident at approximately 7:56 a.m. LAPD Detective Moises Castillo said the girls had a green light at 37th and Broadway. When they began to cross the street, the big rig crashed into them.
"They get sucked in underneath the truck, and another driver actually flags the driver and said, 'Hey, there's somebody underneath your truck,'" Castillo said.
The 12-year-old was described to be in grave condition.
The truck driver and witness called 911 and rendered aid. The driver, who appeared very distraught at the scene, and owner of the truck are cooperating with the police investigation.
"Basically, he didn't see them. He felt something, but it wasn't until that driver that flagged him down that he realized that he actually ran over someone," Castillo said.
The detective said there was no evidence of any alcohol or drugs and that investigators will look at his cellphone data, but Castillo added that so far, there is no evidence that he was distracted behind the wheel.
Detectives had a friend of the sisters' return to where the accident happened. She said she saw everything.
"She pretty much told us that she saw the driver looking down, so she's not sure if he was on the phone... but he had his head down and she tried to get his attention to stop. He continued for a few seconds or a few feet, and he finally noticed her, then he stopped. She ran to render aid, called 911. She actually grabbed her friend's hand and said, 'Hang in there, you're going to be OK,'" Castillo explained.
Castillo later tweeted a photo of the sisters, named Marlene and Amy.
Today these sisters, Amy (left) & Marlene woke up and walked to school. They were struck by a commercial truck. Marlene did not survive and Amy is fighting for her life. Prayers please. @LAPDCTD24 pic.twitter.com/3qBmxmSq88— Moses Castillo (@okaybyemoses) April 5, 2019
The L.A. County District Attorney's Office will determine whether any criminal charges will be filed against the driver.