Deputy Calvillo and Sergeant Craig Newburn were working off duty guarding movie equipment outside the Wagon Wheel Post Bar in Avra Valley. At approximately 7:30pm, they were approached by a patron of the bar who told them there had been a fight in the bar, and one of the participants was now in the parking lot with a gun, waiting for his adversary to come out. Deputy Calvillo and Sergeant Newburn found John Rierson standing next to his vehicle holding a rifle. They spoke with Mr. Rierson and were able to convince him to leave. A few minutes later, Mr. Rierson returned and went inside the bar before Calvillo and Newburn could get to him.

Upon searching Rierson’s vehicle, they located his rifle. Deputy Calvillo secured the rifle in his vehicle just as John Rierson came out of the bar, and a confrontation occurred. As Sergeant Newburn and Deputy Calvillo tried to calm John Rierson down, a jeep pulled up next to Deputy Calvillo. In the jeep were Curtis Rierson, John’s brother, and his wife. John became highly agitated when he saw Curtis. As the deputies’ attention was on John, Curtis Rierson drew a 44 magnum pistol and fired one shot, striking Deputy Calvillo. Hearing the shot and seeing Deputy Calvillo fall, Sergeant Newburn drew his weapon and fired four shots, hitting Curtis Rierson.

Ernie Calvillo was flown to University Medical Center in Tucson; he died shortly after midnight. Curtis Rierson was taken to Northwest Emergency Center in Tucson and was pronounced dead upon arrival.

Deputy Ernest Calvillo was survived by his wife Pat, and two daughters, ages two and eight, as well as numerous family members, including a sister who was married to a fellow officer.