Branford's Walsh Intermediate School was placed into lockdown Wednesday after a threat was called in to the school, according to police.
At the time of the incident, most students had already been released due to a scheduled early dismissal, they said.
Police also increased their presence at all Branford schools out of an abundance of caution.
Investigators later identified a middle school student who they say made the threat against the school, police said. The student was referred to juvenile court.
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Police said there is no ongoing threat to the public.