Four police officers in Mesa, Ariz., have been placed on administrative leave after a surveillance video showed some of them repeatedly punching an unarmed black man and pushing him to the ground during an arrest.

The Mesa police chief, Ramon Batista, released the video to local media on Tuesday after a civilian alerted him to the footage from a building’s surveillance camera, recorded on May 23.

Also this week, police body-camera footage of another arrest of another unarmed black man in Mesa — this one took place in November — was released and posted on YouTube, prompting activists to call for an independent investigation into the Police Department.

Footage of last month’s arrest shows a man, Robert Johnson, 35, speaking on a cellphone on what looks like a balcony of an apartment building before officers emerged from an elevator shortly before midnight on May 23. They were apparently responding to a domestic disturbance call.