Police say the ex-convict who held a Florida school board at gunpoint had been planning to do it for some time.
Panama City Police Chief John Van Etten says Tuesday's date was circled on a calendar found in the trailer where 56-year-old Clay Duke lived north of Panama City.
Duke shot himself after firing at school board members during a meeting Tuesday. No one else was hurt. Before opening fire, he painted a red V on a wall and talked about his wife being fired.
Officials say she worked for the schools, but it wasn't clear whether she resigned or had been fired or what her job was. She was apparently living with her mother in a nearby town.
Van Etten says the shooting was not "spur of the moment." Police also found anti-government paraphanelia in Duke's home.