'Stand your ground' laws in question after death of unarmed 17-year-old.

Interest in Trayvon Martin Shooting Spurred By Celebrity Tweets and Petition

An explosion of social media has catapulted the shooting death of Florida teenager Trayvon Martin into the national spot light, with a single petition calling for his killer's arrest now the fastest growing petition in internet history, according to Change.org.

Martin, 17, was killed by self-appointed neighborhood watch captain George Zimmerman Feb. 26. Just moments before Martin is killed, Zimmerman, who is white, can be heard muttering something in a call to the police dispatcher which many believe was a racial epithet.

Martin, who was black, was carrying only a bag of skittles, ice tea and his cell phone which captured his last seconds in a phone call with his girlfriend before he was shot to death.

Martin's family says that what the girl heard contradicts Zimmerman's claim that Martin was acting suspiciously and was the aggressor in their confrontation.

The family has called for Zimmerman to be arrested

For nearly three weeks the story languished, as did the change.org petition set up for Martin's parents Sybrina Fulton and Tracey Martin. It had a few thousand signatures, but towards the end of last week, as ABCnews.com other media began intensifying their coverage of the story and ce.