The next day, Zimmerman called the SPD again, reporting another suspicious black male lurking in the area.
On October 6 of that year, Zimmerman called in a third report, again alerting authorities to a suspicious black male.
On February 2, 2012, Zimmerman called in a similar report to the SPD.
"According to all records checks, all of Zimmerman's suspicious persons calls while residing in the Retreat at Twins Lakes neighborhood have identified black males as the subjects in the matter," the Sanford Police Department said in a statement after Martin was killed.
The night of the shooting
On February 26, 2012, Zimmerman left his home in his car to go to a store. The 28-year-old called the SPD's non-emergency line to report "a suspicious person" in the neighborhood. Officials instructed him not to get out of his car or approach the person.
Moments later, neighbors reported hearing gunfire.
Just before he was killed, Trayvon Martin was walking back from a nearby convenience store, headed to his father's girlfriend's home. He was carrying a small amount of cash, candy, a soft drink and a phone. He was not carrying a gun.
When police arrived, Zimmerman admitted to authorities that he shot the teen, but said it was in self-defense.
In his police report, Officer Timothy Smith noted that Zimmerman was bleeding from the nose and back of his head after the shooting.
Responding officers were not able to identify Martin when they arrived at the crime scene because he was not carrying identification. His body was transported to the morgue.
After the shooting
The day after the shooting, Martin's father filed a missing person report after his son failed to return home. Officers with the SPD visited Tracy Martin, who later identified his son's body using a picture.
Investigators received a fax from the Altamonte Family Medical Practice on March 8 containing the medical records identifying the injuries sustained by Zimmerman the night of the shooting.
In mid-March of that year, the FBI received a report that Zimmerman had contacted a gun store about acquiring a new firearm because, according to Zimmerman, his "life is in danger, and he needs more guns."
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.