The dress may have been casual, but the message was serious.

Thousands of people, many of them wearing hooded sweat shirts, rallied Thursday evening at the University of Minnesota to protest the killing of an unarmed black teenager last month in Florida.

The rally, which police estimated at 5,500 strong, drew a diverse crowd to Northrop Plaza, including many young adults, teenagers, older people and families with children, wearing not just hoodies, but hijabs, jackets and hats on the cool, windy spring evening.

Many held signs and banners with messages like "Justice for Trayvon Martin" and black-and-white photos of the 17-year-old Martin. Some, like Martin on the night he was fatally shot, carried Skittles candy and iced tea. They listened to speakers, including student leaders and political activists, and shouted back responses, then marched around the mall, demanding justice.

Minneapolis rapper Brother Ali was among the speakers. "I can always wear a hoodie," the hip-hop star said before the rally. "The reality is that I have privilege ... but the reality is also that not everybody does." Americans, he said, are in many ways obsessed with black culture, "but at the same time we have a deep-seated fear of blackness."

Martin was shot Feb. 26 in Sanford, Fla., by George Zimmerman, 28, a neighborhood watch member who has claimed self-defense. Zimmerman's call to a 911 operator in which he described Martin's hoodie and dubbed him "real suspicious" has been labeled racial profiling by protesters.

Thursday's rally, like others held around the country this week, was part of a campaign launched on social media called "A Million Hoodies for Trayvon Martin." Thousands of people, including many celebrities, have posted pictures of themselves in hooded sweat shirts on Twitter and Facebook.

Chela Wilson, 19, of Minneapolis, came with family members, all wearing hoodies. "If we're out at night, we're hoodlums," said Wilson, who is black. "If we're traveling in a group, we're a threat." Despite her frustration, she said her hope is that something positive will come of all the protests.

Organizer Jenny Belsito, 22, a student at Metro State University who used Facebook to put out the call for a Minneapolis rally, said she was pleased by the turnout. "I figured it'd be 30 of my friends here today. Now it's 5,000," she said.

The hoodie, she said, "represents a really dangerous stereotype, something that's deeply rooted." She said her own motivations were personal as well as political. Three years ago, she said, her fiancé, who is black, was wrongly accused of a crime after a woman reported that a tall black man assaulted her and he was misidentified as a suspect.

"It was crazy to me that my son almost lost his father for something he did not do," Belsito said. "That kind of thing happens all the time" in terms of racial profiling.

Anastasia Osho, 32, of Minneapolis, brought her 4-year-old son to the rally. "I felt that injustice for anyone anywhere is injustice for everyone everywhere," Osho said. "It makes me concerned for my son that he could be a target just because he's black."

She said she tried to tell her son what happened to Martin, but he is too young to understand.

"I am angry because this happens so often in our society," Osho said. "There are many Trayvon Martins."

Ronald Davis, 27, who was wearing a sweat shirt with Martin's face on it, said he was hopeful after witnessing the turnout.

"After seeing all the people out here ... I feel better," he said.

Nicole Norfleet • 612-673-4495