RIVERSIDE  (AP) — Police and child-welfare investigators were looking into allegations that a third-grade boy at a Southern California school sexually assaulted another boy several times during two school years, officials said.

Students in an afterschool program at John Adams Elementary School in Riverside told a staffer this week that “they wanted to report something they knew,” Riverside Unified School District spokeswoman Jacquie Paul said Wednesday.

The school’s principal talked to the students and to both boys, leading to allegations of five to seven incidents of sexual abuse that began in second grade and continued into third grade, Paul said.

“One of the young boys apparently was coercing another young boy,” Paul told the Los Angeles Times.

The assaults allegedly took place in class at times when teachers might not see — such as while watching movies — and in the bathroom, Paul told the Riverside Press-Enterprise.

The boys’ names were withheld, and no further details were released about their identities or the alleged incidents because of their ages, Paul said.

The boy suspected of abuse has been suspended and could face expulsion, Paul said.

The school district notified parents of the allegations in a letter Wednesday and was scheduled to hold a meeting for them Thursday night to answer questions.

Police Lt. Val Graham said an investigation has been launched but gave no further details.

Riverside County’s child protective services unit also has begun an investigation.