PHILADELPHIA – The mother of slain teenager Trayvon Martin told a National Urban League gathering in Philadelphia on Friday to use her tragedy to stop the same thing from happening to another child.

Sybrina Fulton blamed Florida’s “stand your ground” law for allowing her son’s killer to go free.

Fulton issued a call to action against “stand your ground” self-defense laws and told the audience that she believes God is using her and her family to make a difference.

She said she was heartened that her message is getting through when, on the way to the civil rights organization’s annual conference, she handed a card bearing her son’s photograph to a driver and he told her, “That’s my son, too.”

“So my message is coming across, and it’s coming across the right way,” Fulton told attendees.

The message, she said, is to use her son’s story to prevent other children from dying the same way.

Fulton supports an investigation into whether her son’s killer could be charged under federal civil rights laws.

A jury acquitted George Zimmerman of all criminal counts in the slaying of the unarmed 17-year-old. Martin was shot and killed during a confrontation with Zimmerman.