Three students walking through the halls of the South Sioux City High School who refused to identify themselves caused the school to be locked down Monday afternoon.
South Sioux City Police responded to the High School around 1:40pm.
Two of the individuals left the building, but one was detained in the office and was questioned by authorities.
The Elementary and Middle Schools were allowed to dismiss at 2:09 pm.
The all clear was sounded at 2:35pm and all students were safe.
There’s no word yet on possible charges regarding the incident.