(CNN) Cellphone video of a teen's violent arrest in San Antonio, Texas, has police and the family at odds over what really happened.

The police say a 14-year-old girl assaulted one of their officers, while the family insists the video shows it was police, not the teen, who threw punches.

The incident

On Saturday, April Johnson and her daughter attended a quinceañera, a traditional coming-of-age party for 15-year-old girls in the Hispanic community. The party ended abruptly when San Antonio police responded to a call for two men fighting.

Police say that when officers arrived on scene, a large crowd had gathered outside the event. Officers say they intervened in a fight between the teenage girl and someone else at the party, pulling them apart. Police say that is when the teen assaulted one of their officers as he was trying to restrain her.

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