When Depelsha McGruder, 43, of Brooklyn, started a Facebook group called "M.O.B.B. - Mothers of Black Boys" earlier this month, she didn't expect that by the end of July it would grow to include almost 117,000 moms from all over the country, all concerned for their black sons in their interactions with police. She also didn't expect that she'd get to meet some of these women for the first time at the Democratic National Convention here.

On Thursday afternoon, McGruder, who has two sons, ages 7 and 4, gathered with about a dozen women outside City Hall. She carried a bag of T-shirts that read: "I Can't Keep Calm, I Have a Black Son."

McGruder said her goal for the group, which changed its name to Moms of Black Boys United, is to create a sustained effort to end police brutality and change society's perceptions of black men and boys. "We don't want our sons to be a hashtag," she said.

McGruder said members of the group decided to convene in Philadelphia for the DNC to put their concerns in the media spotlight.

M.O.B.B. member Crystal Baldwin, 43, of North Carolina, said, "It's not just a protest, it's not just certain racist states, [countering brutality] has to be a national effort."

"We're just moms trying to secure our boys' lives," said Baldwin, who has three sons, ages 7, 8 and 11. "The same moms that go to PTA meetings, drive our sons to basketball games. My sons are still kids, they don't have a voice, so we're here to give them a voice."