The explosion was caused by a car bomb carried in a Thor Motor Coach Chateau RV that was parked outside an AT&T network facility on Second Avenue North in downtown Nashville at 1:22 am on December 25, 2020. Four to five hours after the RV arrived, people nearby were awakened by the sound of rapid gunfire in at least three bursts, followed by a computerized female voice broadcasting over a public address system: "All buildings in this area must be evacuated now. If you can hear this message, evacuate now. "Stay clear of this vehicle", "Do not approach this vehicle", and "Your primary objective is to evacuate these buildings now" were also among the messages broadcast from the RV. The broadcast warned that there was a bomb in the vehicle, a 15-minute countdown elapsed, and the speakers switched to snippets from the 1964 song "Downtown" by Petula Clark.
Responding to reports of shots being fired at around 5:30 am, two police officers arrived at the area. Though they did not hear any shots, they discovered the parked vehicle and heard the warning.They and three other responding officers subsequently evacuated homes in the area and called in reinforcements, including the hazardous devices unit (bomb squad), while a sixth officer stayed on the street to redirect pedestrians.Two of the officers investigated the RV at one point and observed a camera positioned above its rearview mirrorThe vehicle exploded at 6:30 am, while the bomb squad was on its way to the area.