NEW VIDEO — School shooting in Michigan… 3 dead and 8 wounded… Perp in custody…

Video shows students sheltering-in-place inside a classroom. The student who recorded the footage says the voice heard is that of the shooter who was announcing himself as a Sheriff’s Deputy.

‘Sheriff’s office,’ the boy said. ‘You can come out.’

Students exchange glances as one whispers ‘he said it’s safe to come out.’ But one skeptical classmate declined to open the door, saying: ‘We’re not willing to take that risk right now.’

The gunman shouts back something illegible before calling his classmate ‘bro’ and in that sickening moment, classmates began jumping out a window after realizing the self-professed cop was actually the shooter.

The suspected shooter, a sophomore at the school, was arrested within five minutes of the original call, police said and added an on-scene school resource officer assisted in nabbing him.