TRENTON -- New Jersey's largest state troopers union has lambasted pop star Beyonce's Super Bowl halftime show, invoking the name of a trooper slain by a former member of the Black Panther party and expressing "shock and disgust" at the performance.

Calling the display -- which featured dancers wearing black berets reminiscent of those worn by the Black Panthers -- "blatantly anti-police," State Troopers Fraternal Association President Christopher Burgos on Wednesday asked the NFL to distance itself from the show.

"I should remind you, the NFL and Team Owners that NJ State Trooper Werner Foerster was brutally murdered by Black Panther member and convicted fugitive Joanne Chesimard in 1973 on the NJ Turnpike," Burgos wrote in a letter addressed to Commissioner Roger Goodell, a copy of which was obtained by NJ Advance Media on Thursday.

Foerster was killed in a shootout between troopers and Chesimard, who goes by Assata Shakur, and two associates following a traffic stop on the turnpike. After her conviction for Foerster's murder, Chesimard escaped prison and fled to Cuba, where she remains at large. A monument in Foerster's memory was dedicated in November along the stretch of highway where he was killed.

Police groups have criticized pop star Beyonce, claiming her Super Bowl halftime performance was "anti-police."

The pop star has drawn criticism from police groups around the country for the performance of her new single "Formation," which has been described as a "black power anthem." Fans of the singer say the song, the video for which features references to the "Black Lives Matter" movement, is a celebration of black culture.

The National Association of Police Organizations earlier this week expressed similar objections to the NFL, and a pro-police protest is planned outside NFL headquarters in Manhattan Friday. A counter-protest in support of Beyonce is also planned, according to an event page posted on EventBright.com, which called the criticism of the pop star "a racist, ahistorical attack."

Claiming it was not an issue of free speech, Burgos wrote that the NFL "coordinated, approved, paid and made available this message for a world-wide stage."

"In doing so you have willfully dishonored the hundreds of thousands of men and women who took an oath to serve and protect, and sacrifice their lives every day," he continued.

A spokesman for the NFL did not immediately respond to a message seeking comment.

S.P. Sullivan may be reached at ssullivan@njadvancemedia.com. Follow him on Twitter. Find NJ.com on Facebook.