Police investigate a shooting at Rivers Tree Service on White Settlement Road in Fort Worth December 12, 2012.
Fort Worth police are still trying to determine a motive after a shooting Thursday afternoon on the city's west side.
Police responded to calls of shots fired at Rivers Tree Service in the 4600 block of White Settlement Road at about 3:15 p.m.
Officers found the body of 41-year-old Charles Rivers inside the business. Witnesses and neighbors said the gunman was Rivers' 61-year-old father, Greg Rivers.
The elder Rivers' body was found at Ed Collette Park in the 4900 block of West Vickery Boulevard at about 5:30 p.m. Thursday.
Investigators on the scene said it appeared as if the older Rivers died of a self-inflicted gunshot
wound. On Friday afternoon his death was ruled suicide by the Tarrant County Medical Examine.
Charles Rivers death was ruled as a homicide.
NBC 5's Omar Villafranca and Chris Van Horne contributed to this report.