The police union is condemning a decision to strip a police officer of his badge and gun after the use of a chokehold on a suspect.
The president of the Patrolmen's Benevolent Association calls it a political decision, and that it pre-judges the officer involved.
Video shows Officer Daniel Pantaleo using the chokehold on Eric Garner, who police say was being arrested for selling cigarettes illegally.
Garner died after the incident.
He is heard on the video telling officers that he cannot breathe.
The medical examiner says the cause and manner of death is under investigation.
Another officer involved has also been placed on desk duty.
The city is promising a thorough investigation.