“It’s probably one of the hardest cases I’ll ever handle in my career because of the nature of it,” said Captain Boggs, who is black. “Have I ever had to deal with something like this? No, not from a high school.”

Sean A. Courtney, a lawyer for the Stone County School District, told The Associated Press on Tuesday that a student had been disciplined after administrators determined that the conduct code of the school had been violated. Citing privacy rules, he said he could not identify the student or the specific punishment.

The superintendent of the school district, Inita Owen, and the principal of the high school, Adam Stone, could not be immediately reached on Tuesday night. A secretary reached at the high school on Wednesday morning who was unwilling to give her name said that she could not comment at the time.

Mr. Johnson said the account of what happened came from the student’s parents, and that he had not interviewed the student. The Paytons could not be reached to comment on Tuesday and the student’s name was not available. Mr. Johnson said the student, a member of the football team, has continued to attend school.

He said the student was approached from behind by two or three white students who, without warning, put a noose around his neck and pulled it tight. He said the student did not have any physical injuries but “a lot of emotional distress” and fear of retribution for reporting what happened. The ages and grades of the other students involved were unavailable.