Deputies from the department's Palmdale Station responded to reports of a shooting at the 2200 block of East Old Harold Road in Palmdale shortly before 6:30 p.m.
A pool party was underway when a male suspect showed up out of nowhere and began shooting into the crowd, according to authorities.
Three victims, described only as two juveniles and one adult, sustained gunshot wounds and were transported to a hospital with non-life-threatening injuries, authorities said.
It is believed the shooting may have been a random attack, authorities said, but a motive has not been confirmed.
The suspect remains at large, the sheriff's department said.
The investigation remains ongoing.
This is a breaking news story. More details will be added as more information becomes available.