According to a court affidavit released Thursday, Trayvon Martin's mother identified the screams heard on the 911 tape as the teenager. George Zimmerman, the man who confessed to killing Trayvon Martin, appeared in court Thursday, making his first public appearance since the shooting. Judge Mark Herr set Zimmerman's formal arraignment for May 29, with Herr saying he found probable cause to charge Zimmerman. The affidavit also said "Zimmerman confronted Martin," which contradicts Zimmerman's earlier statements about the night he shot and killed the 17-year-old. Zimmerman has been charged with second-degree murder in Martin's death.