Police received calls about 4:25 a.m. PST, reporting gunfire at the house in Northridge, not far from the department's Devonshire station. Officers responding to the calls said they found the four victims lying face-down outside the house, the Los Angeles Times reported. It appeared they had been shot from close range.
Police said the victims were two women in their 20s, a man in his mid-30s and another man in his 40s, the newspaper said. They had not been identified, though police said some lived at the residence and may have been related.
City Councilman Mitchell Englander, who represents the area, said it appeared the shootings were a "targeted, isolated incident." He said the neighborhood is generally quiet and safe.
"We don't want people in the neighborhood to be concerned at all," he said.
City police Cmdr. Andrew Smith said no weapon had been found. Investigators were interviewing several residents of the home, who the newspaper said had been inside at the time of the shooting.