Orlando-area prosecutors are convening a grand jury to investigate the killing of the unarmed African-American teenager Trayvon Martin nearly one month after his death. On Tuesday, the state attorney’s office for Brevard and Seminole Counties said a grand jury will begin hearing evidence next month, one day after the U.S. Department of Justice also announced a civil rights probe of the case. Martin was walking in a gated community in the Florida town of Sanford when he was shot dead by George Zimmerman, a self-appointed neighborhood watchman. Zimmerman claims he was acting in self-defense even though he was the one following Martin. Martin himself was unarmed, weighed 80 pounds less, and can apparently be heard on a 911 phone call pleading for help. Local police have sided with Zimmerman, refusing to arrest him or press charges. On Tuesday, Benjamin Crump, an attorney for Martin’s family, slammed the Sanford police.

Benjamin Crump: “The family does not trust the Sanford Police Department to investigate it fairly and impartially, because the previous lies that they feel they’ve been told by the Sanford Police Department. And it’s sad because had they just arrested George Zimmerman, it would have silenced a lot of their concerns and questions. Self-defense is a legal argument that you make in a courtroom, not an argument you make on the side of the road to police and get to go home and go to bed, or flee, even.”