Police were called to a house on the 7600 block of 18th Street just before 10:45 p.m. Saturday.
Officers found the bodies of three men and a woman inside the home. They died from gunshot wounds.
A fifth person, who has been identified as a suspect, was taken to the hospital with non-life-threatening injuries. Police say the suspect was wounded apparently by someone in the home who confronted him. He was listed in critical but stable condition.
There was no word on what sparked the shooting, but investigators say some gang members were involved. Investigators said the attack did not appear to be random.
The names of the victims have not been released. Two were residents of the home and two were guests.
The Associated Press contributed to this report.