ORLANDO, Fla. — The parents of an unarmed black teenager shot to death by a Latino neighborhood watch captain in Florida have vowed to fight until justice is served.

On Wednesday, Trayvon Martin’s father, Tracy Martin, addressed a large crowd in Manhattan gathered for the “Million Hoodie March” at Union Square.

Trayvon, 17, a high school junior, was unarmed and wearing a hoodie when he was fatally shot last month by a neighborhood watch captain. Trayvon was returning to a gated community in the city. He had just bought iced tea and Skittles at a convenience store. He was unarmed and wearing a hooded shirt.

The man who shot Trayvon, George Zimmerman, 28, has not been charged, and that is causing outrage and accusations of racial profiling. Zimmerman was captain of his neighborhood watch in the Orlando suburb of Sanford, and was licensed to carry a gun.

The case has ignited a furor against the police department of Sanford, with a population of about 53,500 people, and prompted rallies and a protests. The Justice Department is investigating the shooting and has sent in community relations specialists from its Civil Rights Division to address the tension in the community.

A friend of Trayvon’s says she was talking on the phone with him at the time he was shot. The girl says Trayvon told her someone was following him and he said he was trying to get away. Zimmerman has claimed Trayvon attacked him.

A grand jury is expected to meet April 10 to consider evidence in the case.