High visibility garda patrols will continue over the coming days in the areas surrounding all 42 primary schools in Co Carlow.
It comes after 20 of those schools received a threatening email at around 7am yesterday, with 10 schools deciding to close.
The email included details of a threat and a picture of three guns.
The picture is a stock image that can be widely found online.
It is understood that one line of inquiry that gardaí are following is that the email may have been sent to the schools by a group that deliberately sets out to create a large-scale policing response through the spreading of false threats and misinformation.
Gardaí said the threatening email was believed to have been routed through another country and that the credibility of the message was still being investigated.
The garda patrols at the schools began yesterday following the threat.
