Four police officers in the Bronx have been stripped of their guns and badges and placed on modified duty after a video shot by a civilian surfaced of them pummeling a drug suspect, the police said.

The Bronx district attorney’s office said that it and the Police Department were investigating the episode. All the officers are stationed in the 42nd Precinct.

The beating of the suspect, Jateik Reed, 19, occurred last Thursday afternoon on East 168th Street in University Heights after the police say they saw him throw a bag of crack on the ground.

In the video, after officers wrestle Mr. Reed to the sidewalk, four of them repeatedly strike him with their batons and kick him for about 20 seconds. One officer points a canister of pepper spray at the videographer and orders him to “move back.”

Mr. Reed was charged with assaulting a police officer, drug possession, menacing and harassment.

According to court papers, one officer, Jason Vasquez, saw Mr. Reed throw a bag of crack on the ground and saw two bags of marijuana in his hand.

When another officer, Robert Jaquez, approached Mr. Reed, he flailed his arms, refusing to be handcuffed, punched Officer Jaquez in the nose, opening a wound that required stitches, and head-butted him in the cheek, court papers say.

About two hours later, three family members and friends of Mr. Reed’s went to the 42nd Precinct station house and got into a scuffle with the police, court papers say. They were charged with disorderly conduct, obstructing governmental administration and resisting arrest, court papers show.

Mr. Reed’s mother, Schuan Reed, told New York 1 that he “has staples in his head, he has staples in his arm, his eyes were black, his whole entire back is black, blue, purple.”

The police have not released the names of the officers who have been disciplined in the case.