Mary Rae Carter was 79 when she died on November 26, 1984, at North Horizon Health Center, a nursing home in St. Petersburg, Florida. Her death was one of several suspicious fatalities among elderly residents at the facility that prompted a criminal investigation.

Investigators focused on a registered nurse who had been employed at North Horizon since October 2, 1984. The probe identified a pattern: non-diabetic patients were being injected with insulin and suffering fatal hypoglycemic episodes. Other named victims include Aggie Marsh, Stella Bradham, and Leathy McKnight; a fifth patient, 94-year-old Anna Larson, survived an attempted injection and later recovered, providing key evidence.

Court proceedings concluded in 1988 with the nurse pleading guilty to four counts of second-degree murder and one count of attempted murder. She received a 65-year prison term for the murders and a concurrent 30-year sentence for the attempted murder; she later died in custody on August 27, 2007.