Cowell got on the train at the same time as Wilson and her two sisters and stayed on for the six stops until MacArthur. He sat across from her as she stood, sometimes looking directly at her and sometimes away. Wilson's two older sisters were seated.
RELATED: Man accused of killing BART rider Nia Wilson thrown out of court during trial opening statements
"She didn't like BART. She thought it was nasty," Wilson's sister Tashiya said explaining why she opted to stand rather than sit on a seat that may be dirty or have germs on it.
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The video was played during the testimony of Wilson's older sister, Letifah, 27. She had been wounded in the neck in the knife attack and said she still has pain from her injury. She expressed regret for not being able to prevent the attack.
"That was my little sister and I am always supposed to protect my little sister," she said.
Ford asked the judge for a break at one point when she became overwhelmed and physically sick. She regained her composure and resumed her testimony after the afternoon break.
Her sister, Tashiya Wilson, 22, took the stand Monday morning. She said at first she thought that Nia had tripped as she entered the train at MacArthur station after getting off the first train they took from Concord.
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"I was in shock. I was trying to figure out what happened," she said.
She wasn't physically hurt in the attack. She realized her sister was stabbed when she saw blood on her neck and blood coming from her mouth.
RELATED: Judge rules Oakland BART stabbing suspect competent to stand trial
A forensic pathologist testified earlier Monday that Nia Wilson had a two inch-deep cut that cut her carotid artery.
Cowell was not in court Monday and his absence was not explained. He was also absent on Thursday, the previous day of the trial. He is expected to take the stand in his own defense Tuesday.
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