LAS VEGAS (KLAS) — Dramatic cellphone video shows students huddled in a classroom at the Michigan high school where another student allegedly went on a shooting spree that left four students dead and seven others injured. The fourth student died Wednesday.

The video apparently shot by a student in a classroom shows the frightening moments as the students waited to be rescued.

There’s a knock at the door and students can hear someone yell.

“Sheriff’s office. It’s safe to come out.”

But some students are fearful and concerned it might be a trick.

“We’re not willing to take that risk right now.”

When the person outside the door uses the word “bro” another student says that’s a “red flag.”

Panicked students rush toward a classroom window and jump out running toward an officer who guides them into another building assuring them they are safe.

It is still unclear exactly who was at the classroom door.

Police began receiving calls about an active shooter at the Oxford High School in Detroit just before 1 p.m. Tuesday.

A 15-year-old sophomore was taken into custody without incident shortly after police responded. Authorities have learned the 9mm Sig Sauer was bought by his father on Friday.