Beatrice Roberson Cline, a 79-year-old woman from Perris, California, entered the intensive-care unit at Community Hospital of the Valleys suffering from chest pain late on April 4, 1981. She had a history of heart problems and congestive heart failure, making her hospitalization serious, but those caring for her did not initially describe her as unresponsive or near death. Nurse MacDonald remembered Cline as alert and talkative after her arrival in the ICU.
Morphine she had received in the emergency room had relieved her chest discomfort, and for a time she appeared comparatively comfortable.
During the night, however, Cline's chest pain returned and her heart rate became abnormally slow, a condition known as bradycardia. Registered nurse Robert Rubane Diaz was working the night shift in the unit with MacDonald. Diaz gave Cline morphine for her pain and atropine for the slowing of her heart rate. According to testimony later reviewed by the California Supreme Court, approximately three minutes later, at about 1:55 a.m. on April 5, Cline suddenly began experiencing seizures. MacDonald considered them highly unusual, later explaining that they resembled the severe seizures she had witnessed in another cardiac patient only days earlier and were unlike anything she had previously encountered among heart patients.
Dr. Harold Kent responded from the hospital's emergency room. By the time he reached Cline, she was unresponsive and having difficulty breathing. Kent observed slight shivering movements but did not personally interpret what he saw as a seizure. Cline's condition rapidly deteriorated until her heart stopped. Hospital personnel attempted to revive her, and those measures included the administration of lidocaine, a medication routinely used to treat certain dangerous heart rhythms. The efforts were unsuccessful, and Cline was pronounced dead at approximately 2:32 a.m.
At first, Cline's existing cardiovascular disease provided an apparently plausible explanation for her death. What made the case increasingly suspicious was what was happening elsewhere in the same ICU. Beginning shortly after Diaz started working the Perris hospital's night shift on March 29, a succession of patients suffered sudden, extremely violent seizures that were followed by respiratory and cardiac arrest. Several died. Nurses testified that the pattern was striking because they had rarely, if ever, seen such seizures among cardiac patients. Authorities eventually began investigating whether the deaths were being deliberately caused rather than resulting from the patients' underlying illnesses.
After suspicions arose, bodies of patients who had already been buried were exhumed and examined. Toxicologists tested tissue from internal organs for lidocaine. Cline's samples contained quantities that prosecution experts considered far greater than could be explained by routine treatment. Her cardiac rhythm strips also showed a broad QRS pattern, an abnormality prosecution physicians said was consistent with severe lidocaine toxicity. Dr. Dale Isaeff, pathologist Dr. Rene Modglin, and toxicologists Michael Peat, Alphonse Poklis and Randell Baselt concluded that Cline had received a massive overdose. Modglin attributed her death to lidocaine poisoning while identifying arteriosclerotic heart disease as another significant medical condition.
The defense vigorously disputed that interpretation. Diaz maintained that he had not murdered Cline or any of the other patients. Defense physicians proposed that she could have died from a myocardial infarction or possibly complications involving digitalis. A defense pharmacokineticist also argued that Cline's health problems could have reduced her ability to metabolize lidocaine and that the drug concentrations discovered in her tissues could therefore be compatible with medication legitimately administered during treatment and resuscitation. The defense additionally questioned the seizure evidence because MacDonald was the principal witness who described Cline's episode as a seizure. Prosecutors countered that the combination of MacDonald's observations, the abnormal heart rhythm, the amount of lidocaine found after death and the similar medical crises suffered by numerous other patients established a pattern inconsistent with natural deaths.
The investigation ultimately centered on Diaz, who was the common link among the suspicious deaths at the Perris hospital and another similar death at San Gorgonio Pass Memorial Hospital in Banning. Investigators also recovered lidocaine and other prescription drugs from his residence, while syringes containing unusually concentrated lidocaine became important evidence in the case. Authorities examined dozens of suspicious hospital deaths, although prosecutors eventually selected 12 cases they believed they could prove as murders. Cline was among those victims.
Diaz was arrested at his Apple Valley home on November 23, 1981. California formally charged him with 12 murders and sought the death penalty. Eleven of the charged killings involved patients at Community Hospital of the Valleys in Perris, while the twelfth involved a patient who died at the Banning hospital. Prosecutors alleged that Diaz had deliberately administered massive quantities of lidocaine to patients entrusted to his care. No conventional motive such as robbery or financial gain was established, and prosecutors did not characterize the killings as mercy killings.
Diaz waived his right to a jury, leaving Superior Court Judge John H. Barnard to determine his guilt. His nonjury trial began on October 31, 1983, and became a lengthy battle between medical experts over whether the patients had died naturally or had been poisoned. Prosecutors called dozens of witnesses and argued that the repeated pattern of seizures, abnormal cardiac readings, toxicology results, Diaz's access to the patients and physical evidence involving lidocaine demonstrated deliberate homicide. Diaz testified and denied killing anyone.
On March 29, 1984, Judge Barnard found Diaz guilty of all 12 counts of first-degree murder, including the murder of Beatrice Roberson Cline. The court concluded that the evidence established that Cline had been killed with a lethal overdose of lidocaine rather than simply dying from her existing heart disease. Diaz was subsequently sentenced to death. The California Supreme Court reviewed the case and, in 1992, affirmed the murder convictions and death judgment, although it struck 11 redundant multiple-murder special-circumstance findings. Diaz continued to maintain his innocence and remained under a death sentence until he died in prison in 2010.
