Just last week, three schools in Madera and Bullard High School were forced to lock down due to the same nature of calls.
CLOVIS, Calif. (KFSN) -- There were multiple tense moments at Clovis High School on Tuesday.
The parent of a Clovis High School student tells Action News a man was knocking on the door and windows of a classroom during first period.
Somehow, the man was allowed into the classroom.
The man then had a loud, verbal argument with the teacher, which scared many of the students. Another teacher reportedly entered the room to try to diffuse the situation and the man eventually left.
The district says a student misread the clothing of the man and let him in. A parent says the student thought he was a maintenance worker.
Later in the day, around 1 pm, the school was ordered to shelter in place after a threatening call was made to the front office.
Police surrounded the school and determined the call was a hoax.
RELATED: 11-year-old student made false emergency call that locked down three Madera schools, Police say
Nearby Clovis Elementary also sheltered in place as a precaution.
That call is being investigated.
As for the man who entered the classroom, the district says the principal is taking steps to ensure doors are only opened to people with correct credentials shown.