Police have revealed new details about evidence they recovered at the scene of the mass shooting that rocked a Southern California suburb.

The Hawthorne Police Department responded to the 14100 block of Crenshaw Boulevard just after 2 a.m. Thursday after receiving reports of gunshots heard in the area and “multiple people screaming.”

Officers located three adult gunshot victims upon arriving at the scene, who were transported to local hospitals by the Los Angeles County Fire Department.

All three victims sustained non-life-threatening injuries and are receiving medical treatment, according to Hawthorne police.

An additional adult victim was located later at a nearby hospital.

Hawthorne PD recovered one handgun and “numerous spent bullet casings” at the scene. The circumstances surrounding the shooting are still under investigation.

Witnesses at the scene said a group of people gathered in the area got into an argument before the violence started.

No police officer discharged their firearms, according to MyNewsLA.

Screams and at least three bursts of gunfire can be heard in video footage posted on Citizen from the area. At least 10 shots can be heard spread across about a minute of the footage.

The number of suspects in the shooting remains unknown.

Hawthorne is located in Los Angeles County’s South Bay region.