He was just a 17-year-old kid visiting from out of town — an A's-and-B's student with no criminal record, who walked to a convenience store to get Skittles and a cup of iced tea at halftime of the NBA All-Star Game last month.
But George Zimmerman, the self-appointed "neighborhood watch captain" of the Retreat at Twin Lakes development in Sanford, Fla., called 911 and insisted that the black teenager, Trayvon Martin, looked "real suspicious."
Moments later, Trayvon was facedown in a pool of blood on the grass near a pathway, shot once in the head.
The white Hispanic man who shot him, Zimmerman, told the Sanford cops it was a case of self-defense. And 22 days later, anger is still building among activists and on social media that Zimmerman has been allowed to walk free.
"All of this wouldn't have happened if the local authorities had shown some guts," said Wayne Bennett, the Philadelphia lawyer who has written extensively about the case on his popular blog called The Field Negro.
Today, the uproar over the Trayvon Martin case was boiling its way onto the political front burner — both in the hothouse of national cable TV and here in Philadelphia, where activists are working with the local NAACP on a march and candlelight vigil slated for later this week.
Students protested across Florida, civil rights activist Rev. Al Sharpton made plans to meet Trayvon's parents later this week, and the Congressional Black Caucus called for a Justice Department investigation. "Contrary to the flippant way this case has been handled, his life had meaning and purpose," said Rep. Emmanuel Cleaver II. "Trayvon had a family, friends and a future all taken away because of the color of his skin."
You could argue that Trayvon's killing is galvanizing black activists and their allies in the same way that right-wing trash-talking of law student Sandra Fluke re-energized the women's movement.
But it might be more accurate to see the Florida youth as a 21st century Emmett Till, the 14-year-old African-American (pictured at top right) — like Trayvon, an out-of-towner — whose 1955 murder in Mississippi after reportedly whistling at a white woman helped spark the civil rights movement.
With Emmett Till, it was a brutal picture of his open casket that stirred urban communities; with Trayvon, it is the snapshots of a clean-cut youth as well as the 9-1-1 audio tape of a shriek punctuated by a gunshot that is now going viral.
"The kid looks like a Huxtable," said J. Whyatt Mondesire, Philly's NAACP president, referring to the handsome college-bound children on TV's once-popular "Cosby Show."
But in both the 1955 and the 2012 cases, a senseless killing also exposed nerves rubbed raw by deeper societal issues.
Here in Philadelphia, Mondesire said it's been hard to focus on Trayvon's case because he's been busy dealing with the fallout from Pennsylvania's voter-ID law that minorities see as voter suppression.
Bennett, the lawyer and blogger, said he sees the unfounded suspicion about a black teen in the gated community as a symptom of racial anxieties whipped by talk radio and Fox News Channel in the days since President Obama took office. He said he believes people like the gunman Zimmerman are what he calls "color-aroused."
But only one thing seems 100 percent sure in the killing of Trayvon Martin:
The post-racial America that was promised with Obama's election nearly four years ago remains a dream deferred.