Thursday was the first full day of testimony in the trial of a former LAPD officer charged with assaulting a woman under arrest.
Prosecutors say Officer Mary O'Callaghan kicked a handcuffed woman who later died in police custody.
The only witness on the stand was one of the officers on scene during the arrest.
The prosecutor accused him of abiding by the unwritten rule known as the blue code of silence to protect the officer on trial.
Patrol car video cameras show the officer shoving Alesia Thomas in the throat and kicking her in the groin and stomach several times as Thomas was handcuffed and her legs were tied together.
O'Callaghan is on trial for assault under color of authority stemming from the 2012 arrest of Thomas, who was under the influence of cocaine.
Five officers were on scene, including Derrick Ybarra who spent the entire day on the stand.
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Officer Ybarra repeatedly testified he neither heard O'Callaghan use foul language, nor saw her kick Thomas, despite dash cam video showing him standing next to the patrol car during the incident.
Ybarra is also seen on dash cam video whistling to get someone's attention and then pointing at the patrol car camera seconds after O'Callaghan kicked Thomas, but he testified the timing was a coincidence.
The video also captures O'Callaghan saying, "dear God, it's like roping cattle."
The back seat camera abruptly shuts off as Thomas is alone in the car, flailing before she appears to lose consciousness as her head drops back.
She died five minutes after the ambulance picked her up.
