The Rev. Al Sharpton will travel to Sanford, Fla., this week to meet with the family of Trayvon Martin, the 17-year-old shot by a Neighborhood Watch volunteer last week. “You hear a shot, a clear shot. Then you hear a 17-year-old boy begging for his life,” said a lawyer for Martin’s family Friday. Martin was shot and killed by George Zimmerman, a 28-year-old volunteer with the neighborhood crime watch, two weeks ago. Zimmerman has claimed he shot Martin in self-defense and has not been charged with any crime. In one 911 call before the shooting, Zimmerman said there was a suspicious person in his gated community who looked “like he’s up to no good, like he’s on drugs or something.” A call placed by another man moments later reported that a black youth seemed to have been shot and killed after a struggle.