A Sonoma Valley man was arrested Friday night in connection with the death of a man during a fight outside the Valley of the Moon Teen Center in Agua Caliente.

The Sonoma County Sheriff’s Office said Joshua Javier Gonzalez, 19, was booked into the Sonoma County jail on suspicion of involuntary manslaughter. He is being held on $25,000 bail.

Sheriff’s officials said Mario Zamudio Perez, 25, of Sonoma Valley got into a fight with Gonzalez around 5:30 p.m. Friday outside the teen center. Perez was treated outside the teen center and transported to Sonoma Valley Hospital, where he died a short time later, said Sgt. Shannon McAlvain.

An autopsy is scheduled for Tuesday. The sheriff’s report does not mention a weapon used in the fight.

Rene Perez, who was working Friday evening at La Favorita grocery store a block from the teen center, said he saw the police activity outside. Someone came into the store and told him about the fight, he said.

“One punch, that’s what I heard,” he said.

Maria Gomez, a cashier at the store, said she knew Mario Perez. She said a friend called to tell her that he had died in the fight.

“I’m sad. He was a friend,” she said, declining to elaborate about Perez.

Sheriff’s officials would not say what started the fight, but McAlvain said Perez and Gonzalez knew each other.

“This is an ongoing investigation,” he said. “We’re still in the process of determining what happened and how (the victim) died.”

Perez’s death was the fourth homicide this year in Sonoma County, and the first since 15-year-old Nathan Torres was shot and killed outside a party in Windsor in June. In March, Roy Kauwe, 22, of Rohnert Park was stabbed to death in what authorities suspect was a dispute over a woman. In January, Eduardo Caballero, 19, was found dead inside a Roseland home of a gunshot wound to the head.

Though the fight took place in front of the teen center, the two men had not been at the facility Friday evening, according to a visitors log. Gary Nelson, a volunteer who said he was not at the teen center Friday, said Saturday the activity center only accepts teens age 18 or younger.

The teen center sits just feet from busy Highway 12 as it winds through the Sonoma Valley. The Agua Caliente neighborhood is dotted with apartments, taquerias and Hispanic grocery stores.

Residents and workers in the neighborhood said gang activity has become common in the area, but violent crime is unheard of.

“We get burglaries and stuff like that,” said resident Paul Franklin. “But a killing is pretty rare around here.”

Leydi Espinoza, who sells car insurance in an office next door to the teen center, said she saw law enforcement officers Friday evening, but she did not know the reason. She was surprised to learn that there had been a homicide in the neighborhood that she said is normally safe.

“That’s kind of scary,” she said. “You usually just see kids hanging out outside the teen center.”

Sheriff’s officials said Sunday morning there was no information about the direct cause of death. Staff at the Sonoma County Coroner’s Office could not be reached.

Staff Writer Elizabeth M. Cosin contributed to this report. You can reach Staff Writer Matt Brown at 521-5206 or matt.brown@pressdemocrat.com.