CONCORD -- Prosecutors have found two more victims and filed 17 more molestation counts against former Woodside Elementary School teacher Joseph Martin, who now faces a total of 109 sexual abuse charges involving 13 former students, a deputy district attorney said Friday.

The new victims, like the earlier ones, are former students in his fifth-grade class and are all boys. And there could be more victims, said prosecutor Derek Butts.

"The investigation is ongoing," he said. Prosecutors say they have found victims dating back to 2006, but Martin worked at the school since 1991.

Martin, who has pleaded not guilty, is in custody on $10 million bail. He is scheduled to appear Monday in court for a preliminary hearing. The popular teacher -- known for his unorthodox teaching methods that included producing and filming classroom plays -- faces life imprisonment if convicted.

Two civil actions have already been launched against the teacher and district administrators. Two boys claim district officials knew of early complaints about Martin's conduct and that no one reported them to police or Child Protective Services, as required by state law.

One 11-year-old boy claims that on Martin's last day in April, after allegations surfaced and he was placed on administrative leave, the teacher was allowed by district officials to "say goodbye" to his class and took the opportunity to corner the boy and dissuade him from reporting fondling.

"It is becoming increasingly clear that Joe Martin is a depraved sexual predator," said attorney Marc Lewis, who represents the 11-year-old. "These new charges prove that the district knew or should have known about the monster on its campus. We are encouraging additional victims to come forward."

Contact Matthias Gafni at 925-952-5026. Follow him at Twitter.com/mgafni.