John W. Rainwater, a 95-year-old man, died during the early morning hours of April 11, 1981, while being treated in the intensive care unit at Community Hospital of the Valleys in Perris, California. Rainwater was seriously ill with congestive heart failure and was experiencing shortness of breath, an irregular heartbeat, and swelling in his legs. Despite those medical problems, a nurse working that night later described him as alert and in stable condition before the sudden crisis that ended his life.
Registered nurse Robert Rubane Diaz was working the overnight shift with nurses Lois Cheville and Duller. At about 4:00 a.m., Diaz was watching the ICU heart monitors when he told Cheville that Rainwater's heart rate had fallen and that he intended to give him atropine, a medication commonly used when a patient's heart rate becomes dangerously slow. Diaz entered Rainwater's room and soon afterward called out that he planned to administer another dose of atropine. What followed was dramatically different from Rainwater's previously stable condition. He began suffering seizures, followed by cardiac and respiratory arrest. Hospital personnel attempted to resuscitate him, but the efforts failed. Rainwater was pronounced dead at approximately 4:45 a.m.
Rainwater's death initially occurred against the background of severe existing heart disease, making a natural cardiac death plausible. As investigators began examining an unusual series of deaths and medical emergencies at the Perris hospital, however, his case took on a very different significance. A number of patients treated during Diaz's night shifts had developed unusual, violent seizures before suffering cardiac or respiratory arrest. Investigators eventually focused on the possibility that patients were being deliberately poisoned with excessive amounts of lidocaine, a powerful medication used to control certain dangerous heart-rhythm disturbances.
The medical evidence concerning Rainwater became central to the murder case. Prosecution experts testified that his cardiac rhythm strips showed a prolonged QRS pattern between approximately 4:29 and 4:41 a.m., a finding they considered consistent with severe lidocaine toxicity. Tests of tissue samples taken from Rainwater revealed unusually large quantities of lidocaine. Dr. Isaeff, one of the prosecution's medical experts, concluded that Rainwater had received a massive overdose of at least 1,000 milligrams shortly before his death. Toxicologists Peat and Baselt agreed with the conclusion that the amount could not be explained by the therapeutic dosage Rainwater had received. Another prosecution expert, Dr. Modglin, testified that Rainwater died from lidocaine poisoning associated with pulmonary arteriosclerotic heart disease.
Diaz's defense challenged that interpretation. Rainwater was extremely elderly and was suffering from severe congestive heart failure, and defense experts maintained that his physical condition could have made it difficult for his body to metabolize even medically administered lidocaine. The defense argued that Rainwater could have died from his underlying heart disease, possibly complicated by toxicity developing from therapeutic treatment rather than from an intentional overdose. The prosecution's experts disagreed, maintaining that the concentration found in his tissues was far too high to be explained by the documented therapeutic medication. The trial court ultimately accepted the prosecution's interpretation and found that the evidence established that Rainwater had been deliberately given a lethal overdose.
Rainwater was one of a growing number of patients whose deaths drew scrutiny to Diaz. Diaz had begun working the night shift in the Perris hospital's intensive care unit on March 29, 1981. Over the following weeks, numerous patients experienced violent seizures followed by cardiac and respiratory emergencies, with several dying. The Perris ICU was eventually closed on April 24. Diaz then worked at San Gorgonio Pass Hospital, where another patient died after exhibiting similar symptoms while Diaz was on duty. Investigators examined deaths at multiple Southern California hospitals where Diaz had worked and eventually treated a number of the deaths as suspected homicides.
Diaz emerged as the principal suspect. Investigators developed evidence showing that he had access to the patients shortly before their medical crises and was in a position to administer medications through their intravenous lines. Lidocaine was also recovered during a search of his home. Months after the Perris ICU had closed, a construction worker removing drywall discovered a preloaded syringe near one of the former ICU beds. Although its label indicated a 2 percent lidocaine solution, laboratory testing determined that the syringe actually contained a far stronger 23 percent solution. Prosecutors used this and other medical and circumstantial evidence to support their theory that Diaz had secretly injected concentrated lidocaine into vulnerable patients.
Diaz was arrested at his Apple Valley home on November 23, 1981. California authorities subsequently charged him with 12 murders, including the killing of John Rainwater. The prosecution alleged that Diaz had exploited his position as a nurse and deliberately administered massive quantities of lidocaine to patients who were dependent upon hospital personnel for their care. No conventional motive such as robbery was established for Rainwater's killing, and the case rested heavily on medical evidence, Diaz's presence and access, the pattern of similar patient emergencies, and the concentrations of lidocaine found in the victims.
Diaz waived his right to a jury, and his trial before Riverside County Superior Court Judge John Barnard began on October 31, 1983. After months of testimony involving doctors, nurses, toxicologists and other specialists, Barnard found Diaz guilty on March 29, 1984, of 12 counts of first-degree murder. Rainwater was among the victims for whose death Diaz was convicted. The court also found the multiple-murder special circumstance established.
On April 11, 1984, three years to the day after Rainwater's death, Judge Barnard sentenced Robert Rubane Diaz to death. The judge rejected the defense request for life imprisonment without parole. In explaining the seriousness of the crimes, the court emphasized that Diaz had occupied a position of extraordinary trust, caring for seriously ill patients who were particularly vulnerable and dependent upon him for treatment.
Diaz continued challenging his convictions and death sentence through the appellate process. On August 31, 1992, the California Supreme Court upheld the murder convictions and the death judgment, although it struck 11 of the 12 multiple-murder special-circumstance findings as duplicative. In addressing Rainwater specifically, the court concluded that the prosecution's expert testimony and medical evidence constituted substantial evidence that a lethal lidocaine overdose caused his death and that Diaz administered it.
Diaz was never executed. He remained under a sentence of death for more than two decades and died of natural causes on August 11, 2010, while still a condemned California prisoner. John W. Rainwater's death therefore ultimately became one of the 12 murders for which Diaz was convicted, transforming what could initially have appeared to be the death of a gravely ill elderly cardiac patient into one of the central cases in a notorious series of hospital poisonings.
