A mom and her two young children were gunned down as they attended an outdoor gathering in Sacramento, Calif., a shooting that left a 9-year-old girl dead at the scene, according to local reports.

The drive-by shooter opened fire Saturday afternoon; the mom is in critical condition and the surviving child is stable, police told the local ABC affiliate.

A fourth apparent victim, a man, drove himself to the hospital, the report said.

A suspect had not been apprehended by Saturday night. Police said they were investigating whether the shooting was gang-related.