Despite nationwide criticism that an arrest had not yet been made, Sanford Police Chief Bill Lee stated in March of that year that Zimmerman had not been charged with a crime because there were no grounds to disprove his version of events.
On March 15, Zimmerman's father, Robert Zimmerman, wrote a letter to the Orlando Sentinel, stating that his son had been unfairly portrayed as a racist. He noted that his son is Hispanic and grew up in a multiracial family.
The next day, authorities released seven 911 calls from the night of the shooting. In one of the recordings, a voice screams, "Help, help!" followed by the sound of a gunshot.
On March 19, the U.S. Justice Department and the FBI announced they had launched an investigation into Martin's death.
Days later, Benjamin Crump, the attorney for the Martin family, held a news conference stating that Trayvon Martin was on the phone with his girlfriend around the time he was killed. According to Crump, the girl stated she heard someone ask Martin what he was doing, followed by Martin asking that person why he was following him.
On March 22, a petition on Change.org -- created by Trayvon Martin's parents and calling for the arrest of George Zimmerman -- surpassed 1.3 million supporters.
That same day, Lee announced he was stepping down "temporarily" as head of the police department, which had been criticized for its handling of the case.
In April, Zimmerman was charged with second-degree murder.
Zimmerman attended his bond hearing on April 20 with defense attorney Mark O'Mara. During that hearing, Zimmerman apologized to Martin's family for the loss of their son.
On April 23, Zimmerman was released on bail. A judge accepted his written plea of not guilty days after his release.
A medical report by Zimmerman's family doctor, made the day after the shooting, was made public on May 15. The report stated Zimmerman was diagnosed with a fractured nose, two black eyes and two lacerations to the back of his head.
On June 1, Zimmerman was ordered to surrender within 48 hours after a judge revoked his bond, following the prosecution's argument that Zimmerman and his wife allegedly misrepresented their finances when his bond was originally set in April. Two days later, Zimmerman surrendered to authorities and was taken into custody for a second time.
Zimmerman's jail stint ended a few days later, when he was released after posting the required 10% of his $1 million bond.
In July 2012, Zimmerman gave his first public interview to Fox News' "The Sean Hannity Show." During that interview, Zimmerman stated he would not have done anything differently the night of the shooting.
In April of 2013, Zimmerman waived his right to a "Stand Your Ground" pretrial immunity hearing.
In early May, Zimmerman's defense lawyers and prosecutors faced off in a pivotal hearing. A judge declared that most of the information regarding Martin's and Zimmerman's background would be barred from the trial, including Martin's school suspension history.