The Kill Bill moviemaker joined demonstrators at a march in New York City on Saturday (24Oct15) to express outrage over the alleged mistreatment of suspects in police custody, and his speech to the crowd infuriated police officials.

"I'm here to say I'm on the side of the murdered," he reportedly declared, "When I see murders, I do not stand by... I have to call a murder a murder and I have to call the murderers the murderers."

Quentin's remarks came just days after the murder of a police officer in the Big Apple, sparking fury amongst officials.

The director's comments were condemned by New York's top cop, Police Commissioner Bill Bratton, as well as Patrick Lynch of the Patrolmen's Benevolent Association (PBA), who urged officers to boycott the star's films in protest.

Now the head of Los Angeles' Police Protective League, Craig Lally, has backed calls for a boycott, saying in a statement released to the New York Times, "We fully support constructive dialogue about how police interact with citizens (but) there is no place for inflammatory rhetoric that makes police officers even bigger targets than we already are... (He) took irresponsibility to a new and completely unacceptable level... by referring to police as murderers during an anti-police march in New York. He made this statement just four days after a New York police officer was gunned down in the line of duty.

"And questioning everything we do threatens public safety by discouraging officers from putting themselves in positions where their legitimate actions could be falsely portrayed as thuggery."

Philadelphia's police union president John MCNesby has also spoken out in favour of a protest against Quentin, revealing the organisation's board has voted to back a boycott.

"Mr. Tarantino has made a good living through his films, projecting into society at large violence and respect for criminals; he it turns out also hates cops," he says.