Crowds gather in Miami -- part of a series of protests around the country to express anger over the acquittal of the man who shot and killed an unarmed black teenager named Trayvon Martin.<br /> <br />His father spoke of a promise he made the day he buried his son.<br /> <br />. (SOUNDBITE) (English) TRACY MARTIN, TRAYVON'S FATHER, SAYING:<br /> <br />"I vowed to Trayvon that day, when he was laying in his casket, that I would use every ounce of energy in my body to seek justice for him. I will continue to fight for Trayvon until the day that I die."<br /> <br />In New York singers Beyonce and Jay Z joined protests at the headquarters of the New York City police Department.<br /> <br />The crowd held signs calling for a boycott of the state of Florida, where Trayvon Martin was killed.<br /> <br />His mother spoke of what it was like to be in the courtroom where the man who killed her son was acquitted.<br /> <br />(SOUNDBITE) (English) SYBRINA FULTON, MOTHER OF TRAYVON MARTIN, SAYING:<br /> <br />"As I sat in the courtroom it made
