J. Clifford Swanson was a 79-year-old man who died at San Gorgonio Pass Hospital in Banning, California, during the early morning hours of April 26, 1981. He had entered the hospital several days earlier because of a back injury. By April 23, serious complications from diabetes had left him confused and disoriented, prompting hospital personnel to transfer him to the intensive care unit. His death would become the final killing for which registered nurse Robert Rubane Diaz was ultimately convicted in a remarkable series of hospital murders involving lethal quantities of the heart medication lidocaine.
The circumstances developed during the night shift that began on April 25. Diaz had recently begun working at the Banning hospital after the intensive care unit at Community Hospital of the Valleys in Perris was closed amid concern over a cluster of unusual patient deaths. At approximately 5:00 a.m. on April 26, Swanson began experiencing abnormal heart rhythms. Supervising nurse Antoinette Warburton administered 50 milligrams of lidocaine, a medication legitimately used to treat certain dangerous cardiac rhythm disturbances. About an hour later, Diaz administered another 75 milligrams. These recorded therapeutic treatments later became important because the defense argued that the lidocaine detected after Swanson's death could have resulted from legitimate medical care.
At approximately 6:30 a.m., Warburton left the intensive care area for a brief break. When she returned roughly 15 minutes later, she saw Diaz standing beside Swanson's bed. Diaz then walked back toward the nurses' desk carrying a syringe. Almost immediately afterward, Swanson began seizing. His body became rigid, his jaw clenched, and his arms twitched. Within minutes he went into cardiac and respiratory arrest and died. Nurses Morford and Warburton later provided testimony placing Diaz at Swanson's bedside shortly before the seizures began.
Swanson had substantial underlying health problems, creating one of the central disputes in the later murder trial. The defense maintained that his seizures and death could be explained by severe diabetes, dangerously low blood sugar, oxygen deprivation from congestion in his lungs, and possibly excessive potassium administered during the emergency response. A defense expert presented the theory that these medical problems, rather than intentional poisoning, caused the fatal collapse. Prosecutors countered with evidence from Swanson's heart-rhythm recordings and toxicological examinations. An expert testified that changes in his QRS complexes were compatible with an enormous lidocaine overdose, potentially 1,000 milligrams or more. Testing of his tissues revealed substantial quantities of the medication, and prosecution experts concluded that lidocaine poisoning caused his death, with diabetes and arteriosclerotic heart disease contributing to the outcome.
Swanson's death was especially significant because of what had already been happening at Community Hospital of the Valleys in Perris. Beginning in late March 1981, a succession of intensive-care patients on shifts involving Diaz experienced extraordinary seizures, frequently followed by cardiac and respiratory arrest. Nine patients died during a period of approximately three and a half weeks. The Perris intensive care unit was eventually closed, and Diaz obtained work at the Banning hospital. Swanson then suffered a strikingly similar collapse while Diaz was working there. Investigators came to believe that the pattern was not a series of unrelated medical emergencies but a sequence of deliberate poisonings with massive amounts of lidocaine.
Authorities searched Diaz's residence on May 1, 1981. Among the items seized were syringes, an empty lidocaine box, and a vial containing lidocaine. The broader investigation required examinations of medical records, autopsies and toxicological testing of patients who had died at the hospitals. Investigators ultimately focused on a group of 12 deaths that prosecutors believed they could prove were homicides. Eleven occurred at the Perris facility and Swanson's occurred at the hospital in Banning.
Diaz was formally arrested at his Apple Valley home on November 23, 1981, and charged with murdering 12 hospital patients. The case was unusual because there was no eyewitness who testified to seeing Diaz deliberately inject Swanson with a fatal amount of lidocaine. Instead, prosecutors assembled a circumstantial and scientific case based on Diaz's presence during the deaths, the recurring seizure pattern, extraordinarily high concentrations of lidocaine, medical records and testimony concerning what nurses had seen immediately before the patients collapsed. The prosecution did not establish a definitive motive during the guilt phase, and the California Supreme Court later noted that the evidence did not suggest the deaths were mercy killings.
Diaz waived his right to a jury, leaving Riverside County Superior Court Judge John Barnard to determine his guilt. The non-jury trial began on October 31, 1983, and involved extensive testimony from physicians, nurses, toxicologists and other specialists. Diaz denied murdering the patients, and his attorneys challenged the prosecution's conclusions about the effects and quantities of lidocaine. On March 29, 1984, Judge Barnard found Diaz guilty of all 12 counts of first-degree murder, including the murder of Swanson. The court also found the multiple-murder special-circumstance allegations true.
On April 11, 1984, Barnard sentenced Diaz to death after rejecting the defense request for life imprisonment without parole. During the penalty proceedings, prosecutors portrayed the crimes as a profound abuse of the trust placed in a medical professional. Diaz continued to maintain his innocence. His convictions and death judgment were reviewed automatically by the California Supreme Court, which in August 1992 upheld the convictions and the death sentence, although it struck 11 duplicate multiple-murder special-circumstance findings while leaving the judgment otherwise intact.
Diaz was never executed. He remained under a death sentence for more than two decades and died of natural causes on August 11, 2010, while still a condemned California prisoner. Swanson's death therefore ended with a judicial finding that what initially appeared capable of being explained by severe illness and sudden cardiac deterioration was instead murder: the court concluded that Diaz deliberately administered the massive lidocaine overdose that caused Swanson's fatal seizures and cardiac and respiratory arrest.
