A family says after a video shows a woman struck by an officer from Chester, Pennsylvania

CHESTER, Pa. – The family of a woman who has been arrested, captured in a video that went viral, spoke to Action News about this incident.

He tells Action News that his 20-year-old granddaughter is still behind bars Monday night.

"I spoke to him only briefly this afternoon," said a man who introduced himself as Dominique Difiore's grandfather.

Chester police claimed to have assaulted a sergeant this weekend after she and three other people tried to organize a party at the Widner University home. All four were initially removed from the festivities when the police arrived to break up the fray.

"It's what she is, she was partying and that's all I'm going to say," Difiore said. "There is no reason for that."

Difiore says that he saw the now viral video of his daughter being hit by this officer after she allegedly hit him for the first time.

"There is no reason for that – it's unacceptable to use that kind of force – go! It's a kid!" he says.

Chester police said the St. Patrick's Day festivities had become an annual out-of-campus event it was trying to monitor, and that the weekend incident was under investigation.

The department told Action News to watch more footage detailing what led to the now-viral incident.

Difiore faces aggravated assaults, among other charges, and the other three, Shawn Connelly, Tess Herman and Jaylene Westfall, also face charges of assault.

We contacted his lawyer but we did not hear from him.

Senior officers say they continue to watch videos, new arrests may be pending.