Gardai have no authority to warn schools or sports clubs if an employee has been charged with a criminal offence that affects the organisation, the Herald can reveal.
Sean Creed (39) harassed a former student of Malahide School of Music (MSM), where he worked as a self-employed music teacher, over a 16-month period but avoided a jail term with a four-month suspended prison sentence.
He repeatedly sent the girl insulting letters and text mess- ages.
The school has said it is shocked that it was never told of any investigation into Creed.
MSM said it was not aware of the case against Creed until contacted by the Herald, which has learned that gardai had no authority to inform the school of Creed's activities while the investigation was active.
A garda spokesman said it could not comment on individual cases.
However, a source said that if officers believed there was a risk to minors at the school, gardai would inform child and family agency Tulsa, which would assess the information and decide whether to tell the school or club where the adult worked.
Under Children's First Legislation introduced in 2014, there is a statutory obligation on certain professionals and others to report child protection concerns to Tulsa.
Gardai, medical practitioners, teachers, clergy members, social workers and others are required to report concerns.
However, in the Creed case, the Malahide school was not warned. It is not known if officers told Tulsa of any concerns.Tulsa does not comment on individual cases.
On learning of the case, the private north Dublin music school terminated its association with Creed.
"We are shocked that, given the gravity of the allegations against Mr Creed, we were not informed that there was an investigation in progress," said a spokesperson.
"I can tell you Mr Creed is no longer associated with the organisation."
Creed, of Seapark, Malahide, has been ordered to have no contact with the victim and her family for five years.
He pleaded guilty earlier this week to harassing the teenager between February 2014 and June 2015.