SANFORD -- When George Zimmerman spotted Trayvon Benjamin Martin on a rainy February night as the Miami Gardens teen returned from a convenience store with a can of Arizona fruit punch and a bag of Skittles, Zimmerman saw a troublemaker, a “f---ing punk” up to no good, prosecutors said Monday.

So Zimmerman, a neighborhood watch volunteer already alarmed by a recent rash of burglaries in his gated community, pursued Trayvon with a 9 mm semiautomatic pistol at the ready, fatally shooting the Miami Gardens teen. In a fast-moving opening statement, assistant state attorney John Guy described the volunteer as a vigilante on a mission to rid his block of “a--holes” like Trayvon.

The defense countered that Zimmerman was forced into a confrontation he didn’t want. As a concerned citizen trying to protect his neighborhood, Zimmerman only shot to save his own life after he was viciously attacked, his attorney, Don West, told jurors.

The sharply different pictures of what happened on February 26, 2012, in a townhouse complex in this Central Florida city emerged during opening arguments in a case that has grabbed headlines for more than a year and focused renewed attention on the country’s enduring struggle with race. Zimmerman’s delayed arrest sparked civil unrest including marches and protests across the country and in Sanford.

But inside the fifth-floor courtroom where every seat was taken Monday, Zimmerman’s second-degree murder trial is likely to explore particular moments from the night Trayvon was killed, such as the minutes that Zimmerman followed him, the screams on 911 recordings and the extent of Zimmerman’s injuries from his scuffle with the teen.

On Monday, attorneys from both sides addressed those issues in their opening remarks to jurors but asked them to draw contrasting conclusions.

From the prosecution’s perspective: Zimmerman, now 29, didn’t shoot Trayvon, 17, out of self-defense. Nor did he fire the single, lethal shot into Trayvon’s chest because he had to.

“He shot Trayvon for the worst of all reasons: because he wanted to,” Guy said in a courtroom packed with reporters, Trayvon’s visibly upset parents and members of the public.

When it was the defense lawyer’s turn, West spoke to jurors for more than three hours about the shooting, zeroing in on one point: Trayvon was not unarmed.

“He armed himself with the concrete sidewalk,” West said, adding that Trayvon had badly injured Zimmerman in the altercation. “That is a deadly weapon.”

The state opened its case with a jolt of profanity uttered by Zimmerman himself the night of Trayvon’s killing. “F---ing punks,” Guy repeated to jurors three times in five minutes. “…These a--holes, they always get away.” Zimmerman said those words while on a non-emergency call with police, reporting Trayvon as a suspicious person; prosecutors say his phrasing showed the malice and depraved indifference necessary for a second-degree murder conviction.

Guy also tried to portray Zimmerman as someone who wanted to be a police officer, took classes on self-defense law and carried two flashlights and a loaded gun when he stepped out of his car that night. He asked jurors to listen closely to the background screams on a 911 call made by a neighbor during the fight between Zimmerman and Trayvon.