Marie Johnson, a 40-year-old math teacher, was arrested at 7:24 a.m. Wednesday when she arrived for work at Granada High School at 400 Wall St.
Johnson appeared briefly in Alameda County Superior Court in Pleasanton Friday on 24 felony counts that allege that she sexually assaulted a 14-year-old male student from December 2010 to May 2011.
Johnson, a Livermore resident who's being held at the Alameda County Jail in lieu of $1.85 million bail, is scheduled to return to court at 2 p.m. on Tuesday to be arraigned.
Livermore police Detective Joseph Draghi said in a probable cause arrest warrant filed in court today that when police interviewed Johnson on Wednesday she "admitted to committing the above-listed violations."
The charges listed against Johnson in the warrant and the criminal complaint filed against her are four counts of unlawful sexual intercourse with a minor under the age of 16 and 10 counts each of oral copulation of a person under 16 and performing lewd acts on a child.
Draghi said the student, who is now 15, told a high school coach on Tuesday that "he was a victim of repeated molestation."
The student "provided a detailed statement of a long term sexual relationship with Johnson," Draghi said.
Livermore police spokesman Steve Goard said authorities allege that Johnson began having sex with the boy shortly after he finished taking a class from her in December 2010 and sexually assaulted the boy 24 times over a six-month period.
He said investigators don't know why the alleged sexual assaults ended in May but it could have been because that's when the school year ended.
Police believe the alleged sexual assaults occurred in Johnson's car and in other undisclosed locations in Livermore, according to Goard.
Investigators believe Johnson and the boy, who is now 15, formed their relationship through text messages, social networking on Facebook and instant messaging on a smart phone application called "Words with Friends," Goard said.
He said police don't think there are any other victims but they recommend that parents speak with their children about the nature of any contacts with Johnson.
Johnson's lawyer, Elizabeth Grossman, couldn't be reached for comment Friday.