South Hadley, Massachusetts (CNN) -- The 15-year-old girl who hanged herself last January after enduring months of bullying from schoolmates failed to alert others to her plight, the superintendent of South Hadley Schools said Thursday.
The girl, Phoebe Prince, "was apparently a very private person; she bore a lot without talking to friends or with her parents or with anybody at school," Gus Sayer told CNN.
"She didn't reveal to people what she was being subjected to and, unfortunately, until January 7, we were not aware of what she was being subjected to, so [there was] very little way we could have intervened in the bullying."
Sayer cited two incidents that occurred on January 7. In one, a girl walked into a classroom and called Prince "an Irish slut," he said. The name caller was taken to the principal's office and disciplined, he said.
In the other, a girl "said something threatening about Phoebe" to another girl, he said. A staff member overheard the comment and reported it to the principal, who took disciplinary action, Sayer said.
He said it was school policy not to specify what disciplinary actions may have been taken against any individual student, though he said the latter case did not include expulsion and that the student returned to school.
"To our knowledge the action taken was effective in ending their involvement in any bullying of Phoebe," he said.
Prince, who had recently moved with her family from Ireland to South Hadley, hanged herself on January 14 after enduring what Northwestern District Attorney Elizabeth B. Scheibel described to reporters Monday as "a nearly three-month campaign of verbally assaultive behavior and threats of physical harm toward Phoebe, on school grounds, by several South Hadley High School students."
Six students were named in an indictment returned by a grand jury Friday and made public Monday. In addition, Scheibel said three female students received juvenile charges, but she would not clarify if they were among the six named in the indictment.
That left even Sayer confused. "There could be as many as nine, but I believe that six" is the correct number, he said.
Though authorities did not consider that the actions or failures to act by the faculty, staff and administrators of the school amounted to criminal behavior, prosecutor Scheibel called for them to undergo training to learn to intervene more effectively in such cases.
But administrators in the school district, who oversee the education of 2,100 students in four schools, are being unfairly blamed for the death, Sayer said.
Those critics include a number of parents who have demanded that the administrators resign.
"They really don't know what's going on in the schools, but they feel that this shouldn't have happened and that, somehow, it has to be the fault of the schools themselves," Sayer said. "Frankly, I think that grossly oversimplifies the situation."
Sayer said he had received hundreds of vituperative messages from the community. "They are awful," he said, citing one that said he should be "burning in hell."
He said he was trying to ignore them.
None of the six students identified in the indictment remains in school, he added.
Sayer said he supported the punishments meted out to the students.
"If they, as they have been charged, committed crimes, they should face the consequences for those crimes," he said.
But, he added, expulsion is something educators are reluctant to countenance.
"It's a terrible punishment because that changes their whole lives and what they are capable of doing, and they have to figure out a way to renew and complete their education."
CNN's Alina Cho contributed to this story.