The investigation is complete in a fatal Christmas day shooting near Waterloo. Elwin Huffman reports there won’t be any charges filed. Black Hawk County sheriff’s officials released additional details on the incident Tuesday, confirming that the victim’s father, 69-year-old David Buck, was the family member who shot and killed 43-year-old Chad Buck at 1347 E. Airline Highway. Sheriff’s officials say their investigation revealed that an argument between Chad Buck and David Buck progressed to the point in which Chad Buck threatened to kill his father. That’s when David Buck fired the shot that killed his son. Authorities say David Buck and his wife, Kay, both asserted that the shooting was an act of self-defense. On Monday, just three days after the fatal shooting, an ambulance was called back to the same house for another medical emergency. Officials say David Buck suffered a cardiac episode and later died at a local hospital.