The Case of John Jonchuck, father of the victim Phoebe Jonchuck. Alleged to have mental health, anger issues, and possible substance abuse leads him to believe that his daughter is possessed, and murders her.
References:
Pinellas County Clerk of Court
St. Petersburg Police Department Arrest report
https://www.myflfamilies.com/childfatality/reports/2015-005865.pdf
https://www.dea.gov/factsheets/spice-k2-synthetic-marijuana