On November 28, 2016, a violent disturbance at a home in the 1000 block of North Independence Street in Harrisonville, Missouri, left 42-year-old Tammy Lynn Christiansen dead from a gunshot wound to the forehead. Police found Christiansen unresponsive inside the residence and a second victim, Sylvester Harbour, who had been shot in the back but survived.

The attack began when an intruder, identified as 54-year-old Brian G. Parks, entered the house that morning. Harbour woke to find Parks standing over him with a revolver, and a struggle moved from inside the home to the yard. A nearby driver saw the fight, tried to intervene, and was told by Harbour that Parks was the shooter before Parks fled in a vehicle. Officers later arrested Parks; a search of his truck produced a shotgun with spent slugs and a handgun with empty cylinder slots, and he was observed with blood on his clothing and under the influence of methamphetamine. Reports say Parks and Christiansen had been in a prior dating relationship and argued by phone in the weeks before the shooting.

Anyone who knew Tammy Christiansen, Sylvester Harbour, or who saw activity on North Independence Street that morning is asked to share information with investigators.