Mario Cuestas, 53, was arrested last Thursday. He's accused of multiple crimes, including selling meth to kids.
As parishioners left Saturday evening mass, they read St. Leo the Great Parish's bulletin and found an insert drafted by the Diocese of San Jose.
The document stated that a background check was done on Cuestas before he started volunteering in 2012 and that nothing had been flagged.
"You hear things that happen all over, but of course, when it's that close of course it hits home. But we just got to pray, that's all we could do," parishioner Teresa Flores said.
Cuestas worked in the ministry of music and sang regularly at St. Leo the Great Parish.
On Thursday, undercover agents from a special task force, which included the Department of Justice arrested Cuestas at the fire department's administration building.
Department of Justice spokesperson Michelle Gregory says investigators are going through the evidence they have. What they find could lead to additional charges. Right now, Cuesta is looking at possession and sales of narcotics, sex acts with minors, and child molestation. The DOJ, which is heading up the task force investigating the 53-year-old, hasn't yet determined how many potential victims might exist.
ABC7 News captured video of the raid in progress at his office at the fire department's administrative building.
They seized his computer and searched his San Lorenzo home.
The computer could be key, because the DOJ believes Cuestas solicited or contacted some of the alleged victims online.
Cuestas is accused of selling meth to high school students as well as having sex with a 17-year-old.
"He was a good guy. A big part of our church," one woman said.
"I've known him for a while. Like I said, we just keep praying for him. God will judge him. We can just pray for him. Just be there for him," Cuestas friend Jackie said.
Cuestas was a community outreach officer for the fire department and worked with neighborhood associations, schools, and church groups.
"It's very unfortunate being a firefighter because lots of young people, young men and women want to be firefighters," parishioner Joseph Asunsolo said.
Cuestas will make his first court appearance on Tuesday.Katie Marzullo and David Louie contributed to this story.