Henry Lucero Castro, a 65-year-old man, was a patient at Community Hospital of the Valleys in Perris, California, when what initially appeared to be a serious cardiac illness became part of a far more disturbing pattern of deaths inside the hospital’s intensive-care unit. Castro, a World War II Army veteran who was described in later accounts as having worked as a heavy-equipment operator, had been admitted on April 17, 1981, after complaining of dizziness and pain involving his chest, neck
and arm. His physician suspected that he might have suffered a myocardial infarction. At the beginning of the 11:00 p.m. nursing shift, Castro was alert, coherent and able to communicate.
During the hours that followed, his condition changed dramatically. Castro became increasingly agitated and experienced severe chest pain, premature ventricular contractions and ventricular tachycardia. He received morphine and lidocaine, a medication commonly used at the time to treat dangerous disturbances of the heart rhythm. Registered nurse Robert Rubane Diaz was working in the intensive-care unit with licensed vocational nurse Donna MacDonald. That night Diaz telephoned respiratory technician Jesus Sinohui and warned him that a patient in the ICU was having problems and might suffer a seizure. Sinohui went to the unit, and within minutes Castro suddenly sat upright and began convulsing. Emergency treatment succeeded in stabilizing him, and he survived the episode.
For approximately two more days Castro remained in intensive care without another reported seizure. By the night of April 19 into the early morning of April 20, the ICU had become busier. Virginia Bayless, who had suffered a stroke and possible heart attack, had been admitted in a comatose condition, and another patient, Ethel Shaw, was also brought into the unit. Nurse Susan Stroman came from another floor to help Diaz and MacDonald. According to testimony later presented in court, Diaz told another nurse that he needed the additional assistance because he had several seriously ill patients and expected life-threatening emergencies to occur.
The prediction soon appeared ominous. After Stroman finished caring for Bayless, Diaz directed her attention to Castro, saying that he looked strange. Stroman entered Castro’s room, and almost immediately Castro began suffering another violent seizure similar to the one he had experienced two nights earlier. His condition deteriorated into respiratory and cardiac arrest. While staff members worked to resuscitate Castro, MacDonald went to check Bayless and discovered that Bayless had no heartbeat. Attempts to revive her failed, and she was pronounced dead at 1:38 a.m.
Castro was temporarily brought back, but the crisis was not over. He continued to experience recurring seizures and required repeated emergency treatment throughout the remainder of the night. During one episode, MacDonald and Diaz were alone with him. Diaz was administering medication through an intravenous line on his side of Castro’s bed when he handed MacDonald a preloaded syringe, or lidocaine bolus, and instructed her to inject half of its contents into a second IV line. MacDonald told him she was a licensed vocational nurse and was not authorized to give the injection. According to her testimony, Diaz responded that he would cover for her. Suspicious and unwilling to administer the drug, MacDonald instead emptied approximately half of the syringe onto the bed and set the syringe aside. Despite continuing efforts to save him, Castro died at approximately 4:53 a.m. on April 20, 1981.
Evidence discovered afterward transformed Castro’s death from an apparent medical tragedy into a homicide investigation. Several months later, after the Perris ICU had closed, a construction worker found a lidocaine bolus in a hospital bed. MacDonald’s fingerprint was on it. Laboratory testing determined that the syringe contained approximately a 23-percent concentration of lidocaine, dramatically stronger than the concentration indicated on its labeling. Stroman also testified that during the night Castro died, she saw Diaz inject medication into Castro and then throw the used syringe into an ordinary wastebasket. That was contrary to hospital procedure, which called for used needles and syringes to be handled through a designated disposal process.
Toxicology and medical evidence became central to the prosecution. Experts for the state concluded that Castro had received extraordinarily large quantities of lidocaine shortly before his death. One prosecution physician believed that an earlier seizure could have resulted from an overdose of approximately 500 milligrams and that the later seizures were consistent with one or more additional overdoses exceeding 1,000 milligrams. Toxicologists who examined samples of Castro’s tissues similarly concluded that he had received more than 1,000 milligrams shortly before dying. A prosecution pathologist ultimately attributed Castro’s death to lidocaine poisoning. The prosecution argued that Diaz had deliberately substituted highly concentrated lidocaine for the much weaker solution normally contained in preloaded hospital syringes and then used the altered syringes on patients.
Diaz disputed that interpretation of the medical evidence. His defense presented experts who suggested alternative explanations for Castro’s seizures, including inadequate oxygen resulting from low blood pressure, possible alcohol withdrawal, or reactions involving medications he had legitimately received. Other defense witnesses argued that the amount of lidocaine detected in Castro’s tissues could have been consistent with therapeutic treatment. The case therefore depended heavily on competing expert interpretations, the unusual similarities among numerous ICU emergencies, Diaz’s access to the patients, the altered lidocaine syringes and testimony concerning his conduct during the deaths. The trial court ultimately accepted the prosecution’s evidence and found that Castro had been murdered through a lidocaine overdose administered by Diaz.
Castro’s death was not investigated in isolation. After Diaz began working the night shift at Community Hospital of the Valleys on March 29, 1981, an extraordinary series of patients suffered violent seizures followed by respiratory or cardiac arrest. Investigators became alarmed by the hospital’s unusually high number of deaths and eventually examined patient records, conducted autopsies and toxicological testing, and exhumed some patients who had already been buried. Authorities also searched Diaz’s residence under a warrant. Investigators found syringes and lidocaine-related material, including a partially used vial containing a 20-percent lidocaine solution. The prosecution later argued that these discoveries formed part of a larger circumstantial pattern showing that concentrated lidocaine had deliberately been administered to vulnerable patients.
Robert Rubane Diaz emerged as the principal and ultimately the only defendant prosecuted for Castro’s killing. He was arrested at his Apple Valley home on November 23, 1981, following months of investigation into unexplained patient deaths at hospitals where he had worked. He was accused of murdering 12 patients, including Castro, 11 of them connected to Community Hospital of the Valleys in Perris and another to San Gorgonio Pass Memorial Hospital in Banning. Prosecutors alleged that the victims had been deliberately given massive overdoses of lidocaine rather than dying solely from the illnesses that had brought them to the hospitals. No conventional financial, personal or revenge motive was established at trial.
Diaz waived his right to a jury, and his lengthy bench trial began on October 31, 1983, before Riverside County Superior Court Judge John H. Barnard. On March 29, 1984, the judge found Diaz guilty of all 12 counts of first-degree murder, including the murder of Henry Lucero Castro, and found the multiple-murder special-circumstance allegations true. On April 11, 1984, Diaz was sentenced to death after the judge rejected the defense request for life imprisonment without parole. His convictions underwent the automatic appellate review required in a California death-penalty case. In 1992, the California Supreme Court upheld the judgment while striking 11 of the 12 multiple-murder special-circumstance findings as duplicative, leaving the convictions and death sentence otherwise intact.
Diaz was never executed. He remained under a death sentence for more than two decades and continued challenging his conviction. On August 11, 2010, he died of natural causes while still a condemned California prisoner. Castro’s death nevertheless remained legally established as one of the 12 first-degree murders for which Diaz was convicted, a case built not around a conventional weapon or eyewitness to a killing, but around altered medication, toxicology, hospital records, repeated medical emergencies and the testimony of nurses who had watched a disturbing pattern develop inside an intensive-care unit where patients had gone seeking treatment.
