Robert Rubane Diaz was an American coronary care nurse who became infamous as a medical serial killer known as the "Angel of Death". He gained notoriety for murdering 12 elderly hospital patients in California during the spring of 1981. In 1984, Diaz was convicted of 12 counts of first-degree murder and sentenced to death. He spent over 26 years on death row before dying of natural causes at the age of 72 on August 11, 2010.