Balbino Castro was 87 when he died on August 15, 1997, at Glendale Adventist Medical Center in Glendale, California. His death was one of several elderly patient deaths that prompted an investigation into unusually high mortality among patients under the care of respiratory therapist Efren Saldivar.

Exhumations and testing in 1999 found Pavulon, a paralytic agent, in six of the bodies examined, including Castro’s, confirming deliberate poisoning. Saldivar admitted administering Pavulon to patients and later pled guilty to six counts of murder and one count of attempted murder; his victims were elderly patients ranging from their mid-70s to late 80s.

The plea deal reached in 2002 avoided the death penalty and resulted in six consecutive life terms without parole.