Some key events involving the Trayvon Martin shooting case. All dates are from 2012:
Feb. 26: Martin, 17, is shot and killed during a confrontation with neighborhood watch volunteer George Zimmerman, 28, in Sanford, Fla. Martin was returning from a convenience store and carrying Skittles and an iced tea.
March 8: Martin's family asks the Sanford Police Department investigating the teen's death to release 911 tapes that may help explain how he died. Zimmerman is identified by police as the person who confronted Martin.
March 12: Sanford Police Chief Bill Lee says no arrest has been made because there is no evidence to dispute the shooter's claim of self-defense.
March 20: The Justice Department announces it will investigate the case with the FBI and the U.S. attorney's office joining the investigation.
March 22: Sanford Police Chief Bill Lee steps down temporarily, less than a day after city commissioners gave him a "no-confidence" vote.
April 5: A task force convened by Florida state Sen. Chris Smith examines whether changes are needed to the state's self-defense laws in the aftermath of Martin's killing.
April 9: Special prosecutor Angela Corey decides not to take the case to a grand jury, leaving the decision of whether to charge the man who shot Martin in her hands, and eliminating the possibility of a first-degree murder charge. Corey says the decision has no bearing on whether she'll file charges.
April 11: Corey announces that Zimmerman has been arrested and charged with second-degree murder.