Detectives have begun an investigation into allegations of historical abuse at a Cumbria secondary school.
A letter was sent to a number of organisations making claims about incidents at the former Whitehaven School, now The Whitehaven Academy.
Cumbria Education Trust said it had received a letter which made "serious but unspecific allegations".
Cumbria police said it had not directly received a copy but was "made aware" and would "fully investigate".
Lorrayne Hughes, chief executive of Cumbria Education Trust, said it was liaising with police and others to find out whether the claims had "any foundation".
"A letter from an, as yet unidentifiable source, has been sent to a number of organisations including ourselves," she said.
"It makes serious but unspecific allegations spanning almost 20 years.
"Nothing is more important to us than the safeguarding of children and young people.
"Allegations of this nature are understandably taken extremely seriously by all parties and we will assist this investigation in any way we can."
Det Ch Supt Dean Holden, from Cumbria Constabulary, said it was aware a letter had been sent "regarding alleged historical incidents".
"The constabulary has established a multi-agency response with partner agencies to fully investigate the allegations and address any safeguarding interventions that are required," he said.
"The constabulary has not previously received any complaints or allegations in relation to these matters or received a direct copy of the letter.
"However, having been made aware of the allegations by other organisations, the constabulary has implemented a robust investigative response with suitably trained detectives."