ONLY ON ABC7 News.com: Man accuses SFPD of excessive force during Pride Day arrest

SAN FRANCISCO (KGO) -- A San Francisco man claims he was a victim of excessive force when he was slammed to the ground by police during last month's Gay Pride celebration.

San Francisco police have yet to respond, but 24-year-old Tony Nguyen says he was concerned police were using excessive force on a young female protester during a pride week demonstration. Instead, he says he became the target of an officer's violent actions.

On Saturday, June 27 protestors and police tangled outside the old Lexington Club in the Mission District just after the Dyke March.

Nguyen was walking out of a pizza parlor about the same time.

"I decided to go outside and get fresh air to breathe," he said.

Ngyuen said he saw officers on top of a screaming woman trying to restrain her. Cellphone video captured the incident. A police supervisor was nearby.

"I said, 'Hey, you're using excessive force. It's really unnecessary,'" Nguyen said. "He tried to slam me down on to the police car. I seen a bunch of the cops joining up, trying to take me down to the ground. The whole time, I'm telling them, I'm not resisting arrest. Like, I'm willing to comply like anything you want me to do you know."

Police cuffed Nguyen and took him to a waiting police car. He says he asked the officer, "Why am I being arrested? What am I being charged with? And he told me yeah, I have no rights," Nguyen said.

Nguyen was booked on charges of resisting arrest and assault on a police officer.

"I didn't lay a finger on him," Nguyen said.

"The video speaks for itself," said Nguyen's Attorney Kate Chatfield.

"He came out and saw a woman being hurt," Chatfield said, "and he acted best he could in a non-violent way as best he could to address this."

Prosecutors told ABC7 News they've decided not to charge Nguyen, but Nguyen wants to pursue his complaint of excessive force. This was his first encounter with police and he feels as if all his rights were violated when he tried to do the right thing.