The FBI is looking for potential victims in multiple cities of a man accused of sexually assaulting minors over a decade.

Michael Frederick Fangman, 47, was arrested by the Carlsbad Police Department earlier this month on suspicion of sexually assaulting and giving narcotics to alleged victims who ranged in age from 16 to 22-years-old. He has since been charged with 28 felonies in San Diego County, according to a criminal complaint.

Agents with the FBI’s San Diego office are now assisting with the investigation, reaching out to law enforcement in other local communities – including cities in Orange and Riverside counties – where other potential victims may reside. They did not specify why they believe there may be other potential victims in other communities.

The FBI is asking anyone who believes they were victimized by Fangman to complete a confidential online questionnaire the agency has set up at fbi.gov/MichaelFangman.