A Sonoma Valley man arrested in a fatal fistfight outside a teen center was acting in self-defense, his lawyer said Thursday.

Joshua Javier Gonzalez, 19, is suspected of killing Mario Zamudio Perez, 25, also of Sonoma Valley, after the two squared off Friday at Valley of the Moon Teen Center in Agua Caliente.

His lawyer, Walter Rubenstein, said Perez picked a fight with Gonzalez over a Facebook posting and died of head injuries after Gonzalez punched him and he fell against a wall.

Rubenstein said his client didn’t want to fight but had no choice.

“It was a tragic accident,” Rubenstein said. “But you are allowed to defend yourself. If someone punches you, you can punch back.”

Gonzalez was arrested on suspicion of involuntary manslaughter after turning himself in to police. He was released on $25,000 bail.

He appeared Thursday in a Santa Rosa courtroom, where prosecutors requested more time to consider criminal charges.

Judge Dana Simonds ordered him to return to court Oct. 2.

A conviction of involuntary manslaughter carries a maximum four-year prison sentence.

A Perez family member declined to comment on the case Thursday.

Rubenstein said Gonzalez is a former teen center volunteer who was using the center’s computers Friday night to shop for a new car. He works at a local supermarket and had saved up some money, his lawyer said.

At one point, Perez arrived and confronted Gonzalez about the posting, the lawyer said.

Perez yelled at Gonzalez and called him outside, where he swung his fists at Gonzalez, Rubenstein said.

Gonzalez, who Rubenstein said was reluctant to fight, swung back, hitting the other man one or two times at the most.

Perez fell against a wall, hitting his head, Rubenstein said. He later died at Sonoma Valley Hospital, sheriff’s deputies said.

Rubenstein said Gonzalez broke off the fight immediately and fled, fearing Perez might get back up and resume the fight.

At the time, he had no idea Perez was fatally injured, his lawyer said.

But when a friend contacted him later and told him Perez had died, Gonzalez consulted with family and a church pastor before turning himself in, Rubenstein said.

“He felt bad about what happened but he said, ‘I’m not going to run,’ ” Rubenstein said.

You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com. On Twitter @ppayne.