BREAKING NEWS: George Zimmerman in custody, facing murder charges in Trayvon Martin shooting death

SANFORD, Fla. — After weeks of mounting tension and protests across the nation, a special prosecutor has decided to file a charge of second-degree murder against neighborhood watch volunteer George Zimmerman in connection with the fatal shooting of teenager Trayvon Martin, a law enforcement source said.

CNN is reporting Zimmerman is in police custody.

The murder charge is expected to be officially announced at 6 p.m. during a news conference in Florida.

(CBS)  The Feb. 26 shooting death of 17-year-old Trayvon Martin by neighborhood watch volunteer George Zimmerman in Sanford, Fla., spilled over onto the national stage, sparking protests, debate and a personal statement from President Obama. The case has raised questions about race, guns and justice, and led to numerous federal, state and local investigations.

February 26, 2012 - George Zimmerman shoots Trayvon Martin while the 17-year-old is walking back from a convenience store in Sanford, Fla., where he purchased a pack of Skittles candy and iced tea. Zimmerman tells police he killed the teen in self-defense after a scuffle. He is taken into custody but soon released. No charges are filed.

March 8, 2012 - Martin’s parents, Tracy Martin and Sybrina Fulton, create a Change.org petition calling for Zimmerman’s arrest.

March 9, 2012 - Attorney Benjamin Crump tells the Miami Herald he has filed a suit on behalf of Trayvon Martin’s parents to get public records in the case. Crump is best known for his work on the case of Martin Anderson, a black Florida teen who died after being beaten by guards at a boot-camp style detention camp in 2006.

March 15, 2012 - George Zimmerman’s father, Robert Zimmerman, delivers a letter to the Orlando Sentinel. The letter reads, in part: “At no time did George follow or confront Mr. Martin. When the true details of the event become public, and I hope that will be soon, everyone should be outraged by the treatment of George Zimmerman in the media.”

Robert Zimmerman’s letter addresses the race issue. Up until this time, media had been referring to Zimmerman as white, but his father says he is Hispanic.

March 13-15, 2012 - The story goes national. The Atlantic, Crimesider, the Huffington Post, and the New York Times all run stories on the case. Cable news stations and morning news shows interview Crump and Martin’s parents.

- A group called the New Black Liberation militia announces its members will travel to Florida to attempt a citizen’s arrest of Zimmerman.

March 16, 2012 - The Sanford Police Department releases the 911 calls from Feb. 26 to Martin’s family – and later to the public. The recordings include audio of Zimmerman referring to Trayvon Martin as “suspicious,” as well as screams overheard when a neighbor called in a disturbance. Martin’s family believes the screams are his; Zimmerman’s family say they are Zimmerman’s.

March 19, 2012 - The Department of Justice announces it will investigate the shooting.

March 20, 2012 - Benjamin Crump tells reporters at a press conference that he has deposed a young woman who says she was on the phone with Martin moments before he was killed. Crump says the girl told him Martin said, “I think this dude is following me.”

- The Seminole County State Attorney’s office announces they will convene a grand jury on April 10 to hear evidence in the case.