By Jericka Duncan, Natasha Brown and Mike Dougherty
PHILADELPHIA (CBS) -- An entire nation is speaking up for Trayvon Martin, from his parents to the President of the United States.
"If I had a son, he'd look like Trayvon," said the President.
Today, Philadelphia will join the movement to find out why an unarmed teenaged boy was gunned down.
"This was virtually an assassination," said Philadelphia Mayor Michael Nutter. "There was no reason for something like this to happen."
Mayor Nutter supports the protests taking place across the country, in memory of 17-year-old Trayvon Martin of Sanford, Florida. On February 26th at 7:17pm, police say Martin was shot dead by George Zimmerman, a member of a neighborhood watch group, who called authorities moments before the shooting to report a suspicious looking teen, wearing a black hoodie.
Zimmerman has not been charged with Martin's death. He told police Martin attacked him so he shot the teen in self-defense.
"My town watch group wouldn't have that predicament just based on our guidelines and structure," said Mayfair Town Watch president Milt Martelack.
Martelack says his team of volunteers carries cell phones, not guns. He says his eyes are his weapons to fight crime. Police Commissioner Charles Ramsey says town watch groups are expected to report concerns and let police do the rest.
"Police officers go through hundreds of hours of training that involves the use of force," said Commissioner Ramsey. "Much of it involves knowing when it's appropriate to use that level of force."
The large crowd here began their march to Love Park at 7:17 p.m., the time Trayvon was shot by a man working neighborhood watch.
People here are outraged that gunman George Zimmerman walks free.
"I do not even know this 17-year-old but when I heard the story, it touched my heart, and I've never walked in a march. I never felt so strongly."
The 'Philly Hoodie March' grew legs on social media sites, but people here say actions speak louder than words.
"I felt as though I needed to get out and do something. 'Cause, like, tweeting about it, re-tweeting, (updating your) Facebook status... it really isn't going to do nothing."
While nothing can bring back Trayvon, people say hopefully this march and others like it eventually lead to jail time for Zimmerman.
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