Police were called to the 24400 block of Crenshaw Boulevard at about 11:30 p.m., where the victim was discovered shot in the parking lot of the home improvement business.
Torrance police said officers used life-saving measures at the scene before the victim was transported to a nearby hospital. He was pronounced dead a short time later.
The victim's identity was not released.
Investigators seemed to focus on a white Chevrolet El Camino with shattered glass beside it, but would not identify it as being involved in the shooting.
According to Torrance PD Sgt. Ronald Harris, investigators are looking into a possible second crime scene.
"My understanding is that a vehicle theft did occur at a nearby restaurant. It is unclear if these two crimes are linked. Obviously, we're taking everything into consideration, and we're following up on all leads," Harris said.
The second possible crime scene is a Norms Restaurant, located about a mile away from the Home Depot.
Authorities said a motive was not immediately known, and a search was ongoing for a suspect or suspects in the shooting.