Story highlights After the punch, the boy fell to his knees in pain

The man hasn't been arrested

(CNN) It happens so fast you almost miss it.

A man walks down the hallway of a school, crossing paths with a young boy. Suddenly, without provocation, the man reaches down and punches the boy in his stomach. He then casually walks toward the door.

The boy falls to his knees, doubled over in obvious pain. The man pauses, just for a second, to look over his shoulder at the boy, before walking out.

Surveillance video captured this shocking encounter, which happened last week at the KIPP DC Spring Academy in Washington DC. The boy in the video, 7-year-old John Mclean, told CNN affiliate WJLA that the punch to the gut was "real painful."

It was painful for John's mother to see as well. She says the man who punched her child is a fellow parent at the school.

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