Irene Annie Graham was 89 when she was admitted to the intensive-care unit at Community Hospital of the Valleys in Perris on the evening of March 29, 1981, after chest pains following a burglary at her home. She was treated for congestive heart failure and an ongoing heart attack, and was described as having generally regular vital signs during her first hours in the unit. During the overnight shift, nurse Robert Rubane Diaz administered injections into her IV while her primary nurse, Dorothetta Ernest, was briefly away; Ernest reported Diaz said he was giving lidocaine for ventricular tachycardia. A continuous lidocaine infusion was later ordered, and about 15 minutes after it began Graham suffered a violent seizure, stopped breathing and went into cardiac arrest. She was pronounced dead about 6:15 a.m. on March 30, 1981.

Toxicology later showed extremely high lidocaine concentrations in Graham’s tissues. A prosecution expert testified those findings were consistent with an injection of roughly 500 to 1,000 milligrams shortly before the seizure, and a prosecution pathologist concluded her death was due to lidocaine poisoning with underlying heart disease contributing. Similar sudden seizures and arrests occurred in other patients on shifts when Diaz worked, and investigators seized syringes and concentrated lidocaine linked to patient deaths. Diaz was arrested and charged in connection with multiple Riverside County hospital deaths, and the court later found him guilty in Graham’s killing.