On July 14th, 2025, officers with the Brookfield Police Department responded to a disturbance call at a local gas station. Upon arrival, officers made contact with a male subject who appeared visibly agitated. After running his identification, officers discovered multiple outstanding warrants for his arrest. Just moments later, the situation escalated when the suspect attempted to flee on foot. Officers pursued, and within two minutes, the subject was taken into custody without further incident. Body camera footage from the responding officers provides a clear view of how the arrest unfolded.

The next morning, Officer Antiviveros remained in the hospital while officials searched Dennis’s vehicle, uncovering 18 knives, 10 axes, three hammers, a mace fashioned from one-inch piping, a machete, and a coyote trap. Officers also reviewed Dennis’s criminal record, noting charges for criminal trespass, resisting an attempted aggravated assault with a deadly weapon, and multiple threats against retail workers, casino staff, medical staff, and even VA clinic employees. Just a month before the incident, Dennis was charged for threatening VA clinic staff. He allegedly waited in line with an axe slung over his shoulder, telling the clerk: “We do this my way, or your way.” Dennis often called police himself, saying he was armed and angry, warning that if he wasn’t kept calm, “a coroner would be needed.”

Victims also reported he threatened to return with an AR-15 and shoot everyone. In recent years, Dennis’s behavior grew more concerning. He recorded himself expressing disdain for the local police department. Investigators later speculated Dennis may have tampered with his vehicle’s headlight beforehand, hoping it would lead to an incident. Dennis’s father told investigators that he believed the outcome was inevitable. He admitted he thought his son would eventually shoot someone, though he never expected it would be a police officer.