A robocall Monday evening instructing students to enter only through the main entrance of the school on Tuesday, left Union High School parents concerned.
According to authorities, police last night were alerted of an unspecified threat at the high school. Police immediately ensued an investigation and put measures in place to ensure the safety of the students and staff.
Union police say a threat was initiated by a high school senior, who has been was identified Monday. The student was interviewed and ultimately transported to Trinitas Hospital for observation.
According to officials, no weapons were involved and the incident remains under investigation.
UPDATE: (10 a.m.) According to Union Police, the Union High School senior had an argument in one of his classes on Monday and subsequently posted some disturbing information on a social media.