The workplace shooting took place in VA. When the last employee showed up and the camera panned the parking lot the car it started with had a radar detector attached to the windshield. Radar detectors are illegal in VA and are almost unheard of being that obvious in the state.
In the prologue, the unsub turns off the outdoor faucet, attached to a black hose, supposedly to turn off the automatic sprinklers. The obviously undisturbed black hose is clearly coiled up beside the faucet, and there is no set up for automatic sprinklers.