Karen and Paul McCarron’s first child was Katherine, diagnosed with autism in 2004. In September of that year, Paul and Katie moved to North Carolina to live with her paternal grandmother. This move was made so Katie could attend The Mariposa School in Cary, North Carolina, a special school for children with autism and related disorders. Paul and Katie returned home to Illinois on holidays. Karen, who was a pathologist with the Peoria-Tazewell Pathology Group, stayed in Morton, Illinois with their younger daughter Emily, and visited North Carolina occasionally.
After 20 months, the family decided to return full-time to Illinois. Paul McCarron took Katie to their home in Illinois on May 3, 2006. On May 7, 2006, Paul returned to North Carolina to fulfill the last three weeks of his work commitment. Katie remained in Illinois under the care of her mother and maternal grandparents, along with her younger sister. On the afternoon of Saturday May 13, 2006, Karen killed Katie by suffocating her in a plastic bag. Karen later admitted she had been having thoughts about harming Katie for over a year and that three days before Katie was killed, Karen had attempted her to smother Katie with a pillow.
During the trial, Karen claimed that she was influenced by those who believe childhood vaccines might cause autism and felt extreme guilt over vaccinating the autistic child. She said “it was unbearable. I felt I caused Katie’s autism. I felt vaccinating her would not help her. It brought me a great deal of guilt.”
Karen claimed this led to a depression, and the death of the child at her mother’s hands.
Karen was convicted of first degree murder, obstruction of justice, and concealing a homicidal death on January 17, 2008.