Three people were shot to death, and a was fourth wounded, in a dispute that may have been over drugs at a Harbor Gateway apartment complex, officials said.
Police said the incident appeared to be isolated.
"There is no additional danger to the community members in the area," LAPD Capt. Nancy Lauer told reporters Friday.
Police received a 911 call about 5:35 a.m. from a resident who reported hearing eight or nine gunshots in an apartment building in the 1600 block of West 205th Street. When officers arrived, they found three victims.
About a block away, police found a fourth shooting victim, covered in blood, walking near Del Amo Boulevard and Western Avenue, said Officer Christopher No. That person was listed in serious condition at a hospital, Lauer said.
Authorities said a red Dodge Charger and a gray Ford Explorer were seen speeding from the scene.
"We have a number of leads," Lauer said.
The attack did not appear to be random, police said.
"This is not gang-related, this is not race-related," Sgt. Rudy Lopez said. "It appears all the individuals knew each other. It was an argument gone wrong."
Several blocks were cordoned off by police tape as detectives and officers huddled at the intersection of Harvard Boulevard and West 206th Street on Friday morning. Some photographed the building and nearby sidewalk.
Some neighbors walked over to watch, shaking their heads when asked if they had heard anything earlier.
"I saw it on the news," one man said.
The neighborhood is a mix of houses and apartment buildings, most surrounded by wrought-iron fences and many with flowers in the frontyards.
Times staff writer Andrew Blankstein contributed to this report.