ALBANY -- An Albany Middle School teacher was arrested Wednesday on suspicion of a lewd act with a child following reports that he had an inappropriate relationship with a former student, a school administrator said.

Alameda County Sheriff's deputies arrested James Izumizaki, 28, at his Albany home about 7 a.m. Wednesday, authorities said. He was taken to jail, where he was held on $100,000 bail. He posted bail either late Wednesday or Thursday, a sheriff's spokesman said. An email to Izumizaki for comment went unanswered.

The arrest warrant follows an investigation into reports that Izumizaki, who has been a teacher and coach at Albany Middle School for five years, had an inappropriate relationship with a female former student, said Superintendent Marla Stephenson.

Stephenson said the girl is no longer a student at the middle school. Her age was not released.

On Monday morning, a parent with information about the alleged relationship told an Albany High School teacher, who relayed the information to the school's principal, Ted Barone, Stephenson said. Barone told Stephenson about the allegations. District administrators placed Izumizaki on administrative leave and contacted police and child protective agencies.

"We follow all protocols for best practices and hiring: fingerprints, reference checks, everything we can possibly do to ensure quality education and excellent teaching. Unfortunately, you can only do so much when it comes to protecting students. You do everything possible," Stephenson said. "The important thing is we have parents who are vigilant, administrators who are vigilant, who hope that the system works appropriately, and currently, it is."

A substitute teacher will teach Izumizaki's classes on Friday.

Starting next week, the school will redistribute Izumizaki's students among the other nine other sixth-grade classrooms, school officials said. The students will begin in their new classes on Monday. Overall class sizes will still remain at or below the limit of 31, according to a letter sent to parents.

Izumizaki began work in the Albany Unified School District in 2007 as a substitute teacher. He was hired full time as a sixth-grade teacher in 2008, Stephenson said. He was active in student leadership and as a coordinator in the athletic department, where he coached a volleyball and a basketball team.

Stephenson, who said she knows Izumizaki personally, was shocked by the allegations and talked about the importance of maintaining physical and emotional safety for the students and to put a plan of support into place.

"As a superintendent, I am devastated for the district, our community, our students and our staff," Stephenson said.

A parent meeting will be held at Albany Middle School at 5 p.m. Thursday to discuss the incident, Stephenson said. Mental health administrators and interns are also available at the middle school for students or parents who seek support.

The case remains under investigation and police encourage anyone with information about this case, or about any inappropriate conduct or contact between the suspect and minors, to contact police at 510-528-5783.

Contact Erin Ivie at 925-847-2122. Follow her at Twitter.com/erin_ivie. Contact Kristin J. Bender at kjbender@bayareanewsgrop.com. Follow her at Twitter.com/kjbender.