A TEACHING union has denied involvement in letters sent to staff at a school at the centre of an exam malpractice probe.
The PSNI is investigating correspondence received by staff at St Patrick's High School in Keady.
The all-abilities secondary was the top performing non-grammar school in the north last year.
An independent investigation, which looked at GCSE English and maths papers taken in summer 2017, found evidence of cheating by staff.
It uncovered malpractice involving "a number of staff members across exam areas and assessment types".
Two external principals were brought in to oversee summer exams.
Principal Pat McGuckian announced her retirement but stressed that this was due to 16 months of harassment from anonymous letters, not because of the malpractice probe.
Now, the PSNI in Armagh has written to staff telling them officers are investigating letters of harassment, which have been "signed by St Patrick's INTO members and have been ongoing for the last 12 months".
"The current investigation has now broadened and similar type letters have been sent to persons who are not employed by the school. These letters have again been signed off by St Patrick's High School INTO members," an officer wrote.
"We are actively investigating these serious matters and the offences involved include harassment, threat to commit violence, fraud and intimidation. We have an investigation strategy in place and we will pursue all reasonable lines of enquiry."
It is understood that a separate threat, made to a staff member at exams' board the CCEA last month, is also linked to the school. The body said the threat was "abhorrent and designed to cause personal anguish and disrupt our business".
The INTO union said it "unreservedly condemns any threat to harm education workers or their families".
Assistant northern secretary Mark McTaggart said the union was "unequivocal" in its denial of any involvement with the letters.
He urged anyone with information about who wrote them to come forward.
"INTO has sought at every opportunity to assist the school authorities, and the CCMS, to bring it to an end," Mr McTaggart said.
"INTO is urging anyone with information, which could identify the writer or writers, to bring their information to the attention of the appropriate authorities."
