James Carlile, 52, was arrested Feb. 11 at his boat in Antioch where he lives during the school week, police said.
Antioch Unified School District spokeswoman Deidra Powell-Williams said Carlile was placed on administrative leave in mid-January after district technicians noticed he had allegedly been attempting to access Web sites that contain child pornography.
Carlile had been having unrelated technical issues with his computer and had asked to have someone look at it, Powell-Williams said.
After placing Carlile on leave, the district had technicians examine his computer further, and contacted Antioch police on Feb. 3., Powell-Williams said.
The Police Department's forensic computer specialist found that Carlile's computer contained pornographic images of children, police said. Police said the computer was password-protected and that Carlile was the only person who had access to it at the time.
On Feb. 11, Antioch police and the Calaveras County Sheriff's Department served a search warrant at Carlile's home in Valley Springs and at his boat in Antioch.
Carlile was located at the boat and taken into custody. Police said computers taken from the Valley Springs home are being examined to determine whether they also contain child pornography.
He was booked into jail but later posted bail and was released, police said.
Powell-Williams said Carlile has worked in the district as a music teacher for nearly two decades.
He worked at Belshaw Elementary School from 1990-1999 and Black Diamond Middle School from 1999-2004. He was hired at Carmen Dragon Elementary in 2005 and has worked there since, Powell-Williams said.
Powell-Williams said she is not aware of any prior complaints about Carlile's conduct, and said there is no indication he acted inappropriately with any students at the schools where he worked.
The district today activated a phone message that went out to parents about the arrest, and also sent out an e-mail, Powell-Williams said.
She said the district may also organize a meeting on the topic.