A New Jersey transgender woman was arrested Sunday for lighting a pro-law enforcement flag on fire at Philadelphia’s Pride Parade, police said.

Moments before start of #PhillyPride parade one protestor was taken into custody after attempting to lit an American flag. ( photos for @WHYYNews ) pic.twitter.com/KTnPN3rL2a — Bastiaan Slabbers (@BasSlabbers) June 10, 2018

Police charged Ryan Segin, 18, of Woodbine, with attempted arson, reckless endangerment of another person, causing a catastrophe, and other charges, NJ.com reported.

Flag burning is not illegal, as the Supreme Court has ruled it as a form of protected speech under the First Amendment. But police say Segin’s actions are illegal because she lit the thin blue line flag associated with the “Blue Lives Matter” movement on fire in front of a crowd of people, according to the Philadelphia Inquirer.

The Philly Socialists condemned the arrest in a Facebook post Monday, saying that their “comrade” had been arrested by police that should not have been present at the pride parade:

“The police have no place at Pride,” Philly Socialists said in a Facebook post. “Police represent an affront to LGBTQ people and people of color, many of whom have who have died at the hands of police.”

Amber Hikes, Philadelphia’s director of LGBT affairs, wrote on Facebook Monday that she joined three others in helping Segin make bail, adding that officials sent Segin to a men’s prison before deciding to release the protester:

Others have been arrested for flag-burning in public. In May, police arrested three people for burning an American flag during a May Day protest at a park in Charlotte, North Carolina, and charged them causing damage to property.