Robin Ridgeway, 49
Authorities said Ridgeway, a resident of the facility, was sitting under a tree in the yard of Hamilton Villa with two other people when another resident stabbed her in the back. The attack took place about 4:30 p.m.
Sgt. Matt Stone of the Pomona Police Department said Nicole Stewart, a 33-year-old black woman, apparently stabbed Ridgeway because she believed the victim was seeing her boyfriend. Stone said that Ridgeway and Stewart's boyfriend were not romantically involved.
After the stabbing, Ridgeway was taken to the lobby of the facility, where she collapsed. She was taken to a hospital, where she died.
Stone said Stewart tried to run from the scene but police arrested her within minutes. Stewart is being held in lieu of $1-million bail. Officials at the Los Angeles County district attorney's office said prosecutors are pursuing the case, and Stewart is set to be arraigned Aug.12.
Stone said he did not know the extent of Stewart's mental illness and added that he was unsure how she obtained the knife used stab Ridgeway.