A 16-year-old boy who engaged in a sexual relationship with his biology teacher at San Pedro High School last year has filed suit against the Los Angeles Unified School District, alleging officials failed to investigate earlier claims that she was grooming teenage boys for inappropriate conduct.

The boy, who was 15 and in the 10th grade at the time, alleges the then-28-year-old teacher, Michelle Yeh, manipulated his “fragile psychological state,” taking advantage of his young age and naivete to sexual molest and assault him from May to July last year.

Yeh, who was arrested July 21 after the boy told his mother about the relationship, pleaded no contest in Long Beach Superior Court in January to multiple counts of unlawful sex and child molestation involving three boys ages 15 and 16. She was sentenced to three years, eight months in state prison, and ordered to register as a sex offender for life when she is released.

“Sexual abuse has become an epidemic at LAUSD,” said the teen’s lawyer, David Ring. “This lawsuit is about holding the district accountable for its failure to properly screen, train and supervise its teachers.”

The boy was one of three victims, ages 15 and 16, who testified in court that Yeh enticed them with gifts, marijuana and outings to the movies and Disneyland when she began teaching at the San Pedro campus a year ago.

Boys testified that she sent flirtatious text messages, bought them video games and meals, and engaged in a sexual act with one boy in her classroom and another on four occasions in a motel. Prosecutors submitted a list of sexually related text messages to the court.

“I want more kissing,” Yeh wrote in one text to one of the boys, adding emojis with a tongue sticking out. “Next time just sit back, relax and let me make out with you all I want. … Just sit back, relax and let me work my magic.”

The boy filing the lawsuit alleges Yeh flirted with him, showed him acts of favoritism, bought him video games and tennis shoes, took him to Disneyland and to restaurants, and provided him with marijuana, alcohol and prescription drugs such as Xanax.

“After drinking alcohol and abusing drugs, Yeh would engage in sexual intercourse with” the boy, the lawsuit alleges.

The lawsuit, which also names Yeh as a defendant, alleges she committed sexual abuse of a minor, and that the teen did not fully appreciate the wrongfulness of her conduct until he reported it to his mother.

The lawsuit also charges the school district with negligence, breach of mandatory duty, and failure to report suspected child abuse.

“LAUSD was negligent in the enforcement of policies and procedures aimed at allowing a teacher under its supervision to manipulate and harm youth under the teacher’s supervision,” the lawsuit states. “LAUSD owed plaintiff a duty of care, and breached that duty of care, causing significant harm, injury and damage.”

The complaint filed Thursday in Los Angeles Superior Court claims the district failed to act on other reports of Yeh’s misconduct with other students before the teen became involved with her. It alleges officials knew or should have known about her activities grooming students.

“Had (district officials) properly investigated, supervised, trained, and monitored Yeh’s conduct and actions as a teacher on campus at San Pedro High School, they would have discovered that she was unfit to be employed as a teacher,” the complaint said. “By failing to adequately supervise, monitor, or investigate, (the district) allowed Yeh to continue, unhindered, with her predatory conduct directed toward underage students.”

The LAUSD has been a frequent target of lawsuits alleging sexual misconduct by teachers. Perhaps the most notorious in recent years involved Torrance resident Mark Berndt, a third-grade teacher accused of lewd acts with dozens of children at Miramonte Elementary School in South Los Angeles.

Berndt eventually was sentenced to 25 years in prison. The district paid out nearly $170 million in settlements to the children and families who accused him.

Shortly after his arrest in January 2012, , then-Superintendent John Deasy initiated sweeping changes in how the district handles misconduct allegations.

An LAUSD spokeswoman declined to address the lawsuit involving Yeh, saying the district does not comment on ongoing litigation.