BOSTON — Officials at the nation’s first and oldest public school didn’t sufficiently investigate racially charged incidents and failed to address racial hostility, a federal civil rights probe concluded on Monday.

U.S. Attorney Carmen Ortiz said the failure of Boston Latin School administrators to adequately respond to a 2014 incident in which a male student was accused of using a racial slur and threatening to “lynch” a black female classmate while holding an electric cord amounted to a violation of Title IV of the Civil Rights Act of 1964. She didn’t disclose the race of the male student.

The school’s response to other allegations of racial hostility didn’t rise to the level of civil rights violations but demonstrated that officials “paid insufficient attention to issues of race, the concerns of students of color, and the school’s racial climate in recent years,” Ortiz’s office concluded.

Boston public schools Superintendent Tommy Chang said the district has entered an agreement with Ortiz’s office to ensure racial discrimination complaints are handled better at Boston Latin, a prestigious exam school founded in 1635. The school has about 2,500 students, more than half racial minorities, primarily Asians.

Among the initiatives are mandatory racial harassment training for students and staff, establishment of a school official to monitor harassment and discrimination complaints and an annual school-wide racial climate survey.

The NAACP, the American Civil Liberties Union and other groups said the investigation is a reminder to other Massachusetts school districts that it’s their federal duty to address racial harassment.

“It is not often that Title IV is violated so far from the South,” the groups said following the report’s release. “That the Department of Justice brought it to bear here validates the concerns first raised by students and families at Latin.”

Ortiz’s office launched its probe in March after the civil rights groups alleged administrators at Boston Latin had for years failed to address a racially hostile learning environment and inadequately responded to student concerns about racially disparate student discipline and other issues.

The complaint from civil rights activists came after student group BLS Black posted a YouTube video in January complaining about racial hostility. Following months of controversy, Headmaster Lynne Mooney Teta resigned this summer.