On Wednesday, three brothers ranging in age from 8 to 12 were found stabbed to death in the backseat of an SUV near a South Los Angeles elementary school, KTLA reports.

According to the station, authorities say the boys’ father—who was discovered stabbed but alive in the front seat of the vehicle—is their only suspect. He is currently hospitalized in stable condition.

Police say they responded to the scene after receiving a report of assault with a deadly weapon at around 7:15 a.m. From KABC:

John Sorrentino, whose furniture store is next to the crime scene, said he was the one who first spotted the bloody scene and called 911.

“I noticed a guy was all bloody as I walked up to the car. As I approached a little bit closer, I noticed a young boy on a passenger side rear seat crouched against the door, blood all over him, and his eyes were half open, and I looked to see if there was any kind of beat on his chest and there was nothing,” he said. “I yelled at the guy and he was breathing, but gasping. It didn’t look like an attack on him. Doors were closed. He had a box cutter.”

Sorrentino said he then saw another boy bent over a seat, and in the back, a leg of the third boy lying upright. That’s when he ran inside his store and called 911.

“These are horrific incidents,” said Los Angeles Police Chief Charlie Beck. “These are incidents that have scarred not only a community but the first responders that have to handle them.”

[Image via KABC]