Kevin Scott Thorpe, 39, of Rohnert Park, was arrested at his home on suspicion of lewd and lascivious acts and sexual assault on a minor when the alleged victim was 12 through 18 years old, sheriff's Sgt. Spencer Crum said.
Thorpe was a 28-year-old counselor at the time, and the assaults allegedly occurred at Thorpe's Sonoma Valley home and at the Hanna Boys Center located at 17000 Arnold Drive in Sonoma, Crum said.
The alleged victim did not disclose the assaults at the time because he was afraid of getting in trouble or kicked out of the Hanna Boys Center, and he fears there were sexual abuse of other minors, Crum said.
The alleged victim, now 23, reported the alleged assaults June 1, and investigators felt there was sufficient evidence that they occurred, Crum said. Detectives also believe there may be additional victims or others with information about the case.
Thorpe was booked into Sonoma County Jail and is being held under $250,000 bail.
Hanna Boys Center executive director Brian Farragher did not return a call for comments Monday afternoon.
He has been executive director of the center since 2014. The center has an on-campus high school and has been providing "a haven of hope" for struggling youth since 1945, according to its website.