NEW YORK – Staten Island teachers know how to send a message, and they’re putting their activism skills to good use as they continue to speak out against their union’s involvement in an anti-police rally last month.

Hundreds of educators from across the island are purchasing t-shirts reading “New York’s Brightest Support New York’s Finest, #ThankYouNYPD” to make a collective statement during the first week of school, DNAinfo.com reports.

The inter-union kerfuffle stems from the participation of United Federation of Teachers Michael Mulgrew, and national American Federation of Teachers union boss Rhonda Weingarten, in an anti-police march Aug. 23 led by Rev. Al Sharpton.

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The union-endorsed event aimed to protest perceived police brutality in the case of Eric Garner, a Staten Island father of six who died July 17 after the 43-year-old asthmatic was allegedly put in a choke hold by NYPD officers during an arrest for selling untaxed cigarettes, according to the news site.

Educators immediately revolted against the UFT’s participation in the rally, with more than 135 joining the Facebook page “UFT members for the NYPD,” and more than 1,000 others signing an online petition calling for Mulgrew’s resignation.

So far, nearly 550 t-shirts have been sold by the printing company Special Tees, one of several selling pro-NYPD t-shirts through the Facebook page, DNAinfo reports.

“It started out as just a couple of teachers from a school who came in and ordered shirts, and word of mouth has spread, and we’ve been getting calls ever since,” Special Tees director Vincent Bonomi told the news site.

“There are a lot of schools on Staten Island that are ordering them – from the South Shore to the North Shore and everywhere in the middle,” he said of the shirts, which are selling for $6.

Despite an attempt by the UFT and other supporters of the August rally to paint the event as a peaceful protest –  one that simultaneously supports the NYPD while calling for a thorough investigation of the Garner case – the march has also significantly soured relations with the police union.

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“What the Rev. Al Sharpton is trying to do is take due process from a New York police officer,” Patrolmen’s Benevolent Association President Pat Lynch told the New York Times. “Every demo with Al Sharpton becomes and anti-police rally.”

Sergeants Benevolent Association President Ed Mullins agreed with Lynch, and pointed out that many NYPD officers are married or related to a city public school teacher, which essentially means the UFT wanted its members to protest their relatives.

The UFT’s Facebook page, which exploded with negative comments about the union’s participation in the march, was filled with similar sentiments, the Times reports.

“It’s clear that Mr. Mulgrew totally misread his membership,” Mullins said.

Either that, or union bosses like Mulgrew and Weingarten value their political ties with radical groups like Sharpton’s National Action Network more than their members.