Police were called to a primary school after a pupil allegedly brought a KNIFE to school and threatened another child.
Staff dealt with the 'incident' at Hermitage Primary School, Helensburgh, Argyll and Bute, on November 21, before cops were called in the following day.
But it was only after the weekend that parents were informed by the local authority.
A parent at the school, speaking on condition of anonymity, said pupils were scared to return.
The parent said: "Parents were not told about the incident initially.
"No parents other than those of the child who made the threat were contacted.
"We only found out when our children told us when they were home.
"I feel very let down that the school didn't issue a statement sooner that let us know a violent incident had happened and it was being dealt with appropriately.
"I understand they can't disclose certain information, but to withhold the entire matter from parents and have us hear about it third-hand is disgraceful.
"Children are terrified about returning to school.
"There is all sorts of hearsay circulating now and without solid facts, we cannot comfort our children that it's been dealt with appropriately and they will be safe."
An email sent to parents by Argyll and Bute Council said: "Following an incident on Thursday, November 21, it is important that parents and carers have assurances that all appropriate procedures have been followed through with the education department and Police Scotland and that the safety of all children has been, and remains, the school's priority.
"As the incident is now in the hands of Police Scotland, please understand that my scope for discussing any related detail is limited.
"However, going forward, rest assured that the school will work in partnership with all appropriate parties, including parents and carers, to support the safety and wellbeing of all children, and address any concerns."
A spokesman for Argyll and Bute Council added: "An incident took place at Hermitage Primary School on Thursday [Nov 21].
"Staff followed appropriate procedures and the police were called.
"We would like to reassure parents and carers that the safety and wellbeing of pupils is our priority.
"Anyone with any concerns is asked to get in touch with the head teacher."