The Arlington, Texas, police recruit who fatally shot an unarmed college football player during a break-in at a car dealership early Friday has been fired for “exercising poor judgment,” the police chief said Tuesday.

Christian Taylor, 19, was fatally shot by Arlington Police Officer Brad Miller, 49, after police were called to a break-in report at the Classic Buick GMC dealership at around 1:06 a.m., police said.

Miller, a recruit officer who was undergoing supervised field training, entered the building alone and without telling other officers, setting into motion a chain of events that led to the deadly shooting, Arlington Police Chief Will Johnson told reporters Tuesday.

Miller told investigators he feared for his safety and thought he would be overpowered, and that he believed he was alone even though his training officer was four feet away, Johnson said.

“This fear and feeling of isolation was the result of his poor decision to enter the building without assistance and without an arrest plan,” Johnson said.

Police were called to the dealershipafter Taylor allegedly kicked in the windshield of a car and then crashed his Jeep into a showroom door, police said.

Police found Taylor roaming inside the dealership, and an officer spoke with him through a glass door and ordered Taylor to get on the ground, Johnson said. Taylor refused, and held up a set of keys and told the officer he was there to steal a car, Johnson said.

Miller and his supervising officer, Cpl. Dale Wiggins, were tasked with setting up a perimeter. After Wiggins stopped to talk with the officer who made contact with Taylor, Miller saw the crashed car and entered the dealership on his own and without telling other officers, Johnson said.

That decision put the other officers at risk, Johnson said, and Wiggins had to rush to rejoin Miller. By the time he arrived Taylor was allegedly cursing and moving towards Miller in a threatening manner, Johnson said.

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