Diane and Mark Staudte lived in Springfield, Missouri and had three children – one son Shaun, and two daughters, Rachel and Sarah. In April 2012, Mark died of what appeared to be “natural causes” at the age of 62. Five months later, Shaun died “from prior medical issues” at the age of 26. Less than one year later, in June 2013, Sarah, 24, was hospitalized and almost died. It was Sarah’s close call that had police reinvestigate the deaths of the Staudte men.
Police discovered that Diane poisoned both Mark and Shaun by putting antifreeze in their drinks, and Diane and her daughter Rachel, 24, had done the same to Sarah. Sarah suffered permanent brain damage and lives in an assisted living center. Diane and Rachel Staudte pleaded guilty to avoid the death penalty and will spend the rest of their lives in jail. Diane’s attorneys say Diane “has mental disorders from multiple concussions, to PTSD, and has features of autism.” At her trial, daughter Rachel said her mother had told her what to do. ABC 20/20 will air its investigative report on the Staudte family on Friday, April 1 at 10pm.