By sheer logistics, Ruth Donnelly and Dorothy Johnson-Speight might have never met.

In 2001, Johnson-Speight was 52, living in the Mount Airy section of Philadelphia, working as a mental health therapist. Donnelly was 43, living in Olney, and working in education.

Five miles separated them. They lived in different worlds.

But profound tragedy - and coincidence - linked the two: Both lost their sons to murder.

Both sons were killed by the same man, just five months - and two blocks - apart.

On Tuesday, the two mothers, bonded in that unthinkable way, took the stage in Aviator Park in Logan Square to tell their stories and deliver one simple message: They are tired of going to funerals.

At a morning rally, hundreds turned out for the gun-control demonstration, which called on politicians to pass "common-sense" legislation that would impose stricter background checks and limitations on purchasing semiautomatic weapons.

"Stopping gun violence takes courage - the courage to do what's right, the courage of new ideas," declared former Rep. Gabrielle "Gabby" Giffords of Arizona, who suffered a severe brain injury in January 2011 when a gunman sprayed bullets at a crowd of constituents gathered for a town-hall meeting.

"I've seen great courage when my life was on the line," Giffords said. "Now is the time to come together, be responsible. Democrats. Republicans. Everyone. We must never stop fighting."

Appearing alongside multiple politicians, including Rep. John Lewis of Georgia, Giffords was just one of many who spoke at the rally, sponsored by CeaseFire PA, Giffords' political action committee Americans for Responsible Solutions, and Mothers in Charge, a gun-control advocacy group founded in Philadelphia.

Sen. Chris Murphy of Connecticut, now known for his 15-hour filibuster earlier this year for gun control, helped kick off the event.

"I'm proud of the Democratic Party because we are making the fight against gun violence a seminal part of our convention this year!" Murphy shouted to the group of attendees, who chanted and clapped as they licked popsicles to stay cool in the unrelenting heat. At times, attendees wiped away tears.

Some in the crowd had been affected by gun violence. But nearly all carried signs - signs for children who had been killed, for Orlando victims, or for touting a political message.

"We need to stop the carnage," read one. "Newtown Remember," read another that featured a photo of Ana Marquez-Greene, who died in the 2012 Sandy Hook Elementary School massacre in Newtown, Conn.

For more than an hour, speakers took the stage and called on legislators to unite in cracking down on guns. Few were as specific as former Gov. Ed Rendell, who openly criticized Pennsylvania Sen. Pat Toomey and his stance on gun control.

"We have to send Pat Toomey a message that lip service is not good enough," Rendell said, advocating for Democrat Katie McGinty, who is aiming to knock Toomey out of office in November. "We want action and we want action now."

A spokesperson for Toomey did not return a call for comment on Rendell's remarks.

Second Amendment advocates "say gun control would not have stopped Orlando," Rendell said, referring to the shooting at an LGBT-friendly nightclub last month. "Well let me ask you a question: If the fellow who came into the bar . . . if he didn't have an assault rifle and he had a revolver, do you think he would have killed 47 people? Not on your life."

Yet in the rally's most somber moments, attendees watched - sometimes in near silence - as mother after mother told stories of burying their own children.

"This is difficult for each and every one of us to stand here," said Johnson-Speight, who founded Mothers in Charge, which now touts hundreds of members in Philadelphia. She turned to Donnelly.

"We found out that the same person who killed her son in July killed my son in December," Johnson-Speight said. "We've been joined at the hip ever since."

In July 2001, Donnelly's son, Justin, was 19 when he was stabbed to death while sitting on the front porch of a house on Champlost Avenue in Olney.

Five months later, Johnson-Speight's son, Khaaliq Johnson, 24, was shot in a dispute over a parking spot.

What sealed their mothers' fateful meeting was timing - and luck. Johnson-Speight saw Donnelly on TV, speaking about her son's death. Understanding her pain, Johnson-Speight paid Donnelly a visit.

Within minutes, an eerie detail emerged: Each revealed that witnesses and police found that the man who killed their sons owned pit bulls. And the two were murdered just blocks apart.

They knew, they said, that the killer had to be the same man. (Police eventually arrested Ernest Odom, of Philadelphia, for the murders. He is currently serving two life sentences.)

"We've been supporting each other ever since," Johnson-Speight said.

"But there is no such thing as closure here," she said. "This is a chapter that will never be closed. My life has been changed."

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