A woman tried to light a flag on fire amid crowds that had assembled for Philadelphia's Pride parade Sunday, police said.

ReeAnna Segin, 18, of Woodbine, N.J., was arrested around 12:10 p.m. at 12th and Locust Streets, authorities said. Photos taken by freelance photographer Bastiaan Slabbers showed the arrest.

While flag burning is not illegal, police said Segin tried to set the blaze amid a crowd. She was charged with attempt to commit arson, risking a catastrophe, recklessly endangering another person, and possessing an instrument of crime, police said.

The District Attorney's Office on Wednesday dropped the arson and catastrophe charges — both felonies — but said Segin still faces the remaining charges, which are misdemeanors. Officers found road flares protruding from Segin's backpack, which also contained a can of paint thinner and a blue lighter stick, authorities said.

Police described the flag she allegedly tried to burn as a "a thin blue line American flag." It had black and white stripes along with a blue stripe. On social media, some people referred to it as a Blue Lives Matter flag.

Blue Lives Matter, a movement to honor police officers, was created in response to Black Lives Matter, a movement that has called out police killings of people of color.

Amber Hikes, Philadelphia's LGBT affairs director, said Monday evening on Facebook that she helped post Segin's bail. Hikes also said Segin, a transgender woman, had been sent to a men's prison before being bailed out.

Some people, including the Facebook group Philly Socialists, questioned the arrest and rallied in support of Segin.

As of Monday, more than $1,800 had been raised to help Segin with court fees and other charges. Philly Socialists said it and another group, Philly for Real Justice, were assisting Segin.

Editor's note: Police publicly identified the suspect by her birth name, Ryan Segin. The name she uses as a transgender woman is ReeAnna Segin. The Inquirer and Daily News have updated this story to identify her as ReeAnna.