PETALUMA (KPIX 5) — A violent altercation with a Sonoma County Sheriff’s Deputy left a teenage girl bloody and handcuffed in Petaluma, and now she is suing the department.

The video begins calmly enough, with a Sonoma County Sheriff’s deputy rolling up to a pickup where a man and woman have been arguing.

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Amid the screaming of relatives, the deputy ends up tackling the woman’s sister to the ground when she tried to walk away. 19-year old Gabbi Lemos’ face was bruised and bloody when she was arrested. She later claimed police brutality and sued the deputy.

One day later she learned the county was charging her with resisting arrest.

“This is a good example of why departments should equip their officers with body cameras,” KPIX 5 Law Enforcement Analyst Howard Jordan said.

Jordan is the former police chief of Oakland.  He says the trial provides a close look at how body cameras can show context around an altercation with police.

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“You know, one of the things the public have to understand is when an officer gives you an order – whether you like it or not – you have to comply,” Jordan said.

Gabbi’s trial took an unusual turn Wednesday when the judge decided to allow evidence that had previously been thrown out.

The judge allowed prosecutors to play audio from a phone conversation Gabbi had with her mother from her jail cell the morning after the altercation. In that audio, you can hear both women using racial slurs referring to the deputy. Gabbi uses the “N” word.

“It might sway a juror to feel like ‘was this a racial thing?’” Marni Wroth with the Justice Coalition for Andy Lopez said.

But awful language aside, activist Marni Wroth hopes the trial is also an opportunity for residents of Sonoma County to hold their law enforcement accountable for the way they handle heated situations.

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“The deputy appears to have no control over a situation that he could have deescalated,”