When officials at the Community Hospital of the Valley in Perris, California notice a suspicious cluster of patient deaths, a whistleblower contacts the coroner's office. The resulting investigation leads to the exhumation of 38 bodies from local cemeteries. Tissue analysis confirms the level of the muscle relaxant drug Lidocaine in these bodies is 10 to 20 times higher than normal. Whereas an average dose is 100 milligrams, they contain 1000 to 2000 milligrams - enough to kill. Investigators dig deeper and quickly discover one particular nurse was on duty when each of the patients died. His name is Robert Rubane Diaz. Police raid Diaz's home and find empty Lidocaine boxes in the trash. Prosecutors charge him for the murder of 12 patients and delve into his past to uncover his possible motive to kill. They reveal he's a fantasist, resentful of the fact he's not smart enough to be a Doctor. They theorise he engages in a dangerous game of life and death - purposely worsening patients' conditions with overdoses of Lidocaine, before bringing them back from the brink of death in the presence of medical doctors to make himself look good. But then, somewhere along the line, he discovers he gets a kick out of killing and the body count quickly rises. The evidence presented at his trial is damning and the judge sentences Diaz to death by lethal injection. After 26 years on death row, Diaz died in 2010 from natural causes. He never admitted his crimes.