CLARK — Arthur L. Johnson High School was under an active lockdown for most of the school day while police worked to investigate what school officials are calling an as-of-yet “unsubstantiated” threat about a potential weapon on the premises. The lockdown was lifted as of 2 p.m. when classes, all after school activities and sports resumed normal schedule.

“Please know that the safety if our students is paramount,” school officials said via Nixel alert at approximately 10:47 a.m. on Thursday, “We are working directly with the police, who are present on the property at this time.”

Students from Union County Vocational Technical Schools that would have been dropped off at ALJ have been taken to the public library.

As of 11:30 a.m. the school remained in lockdown with police from multiple Union County towns on scene. The Clark Police asked that parents refrain from calling the school and said, “all students are safe. The incident is being investigated pursuant to the School Threat Protocol. You may notice a large police presence; this is normal protocol and should not be cause for alarm. Once police deem that the school is safe and that a normal school day can be resumed, this will occur.”

Police were unable to provide any additional information to Leader staff.

This is a developing story. The Leader will provide additional information as it becomes available.