One speaker at next week's Democratic National Convention is likely to provide a deeply personal take on the impact of police brutality. Who is Gwen Carr? Eric Garner's mother left her career as a subway train operator in the wake of her son's death to serve as a leader of the modern civil rights movement, according to The Wall Street Journal.

For decades, Carr lived a quiet life; The Wall Street Journal reported that she lived in Staten Island and spent 22 years with the Metropolitan Transit Authority (MTA). In an interview published on former Secretary of State Hillary Clinton's presidential campaign website, Carr said she found out about her son's death while she was at work:

I was at work when I started to hear about it, and when I got home and found out that my son had been murdered by police, it just took everything out of me. It went deep. They stole my heart; they ripped it out. I mean, my soul was crushed. He was my firstborn, and he didn’t deserve that. And that day, I will never ever forget as long as I live.

Police approached Garner on the sidewalk; according to CNN, they believed he was "selling illegal cigarettes." Though Garner put his hands up, a police officer put him in a chokehold and wrestled him to the ground. Garner's last known words, "I can't breathe," are heard on a video that captured the entire incident and sparked international outrage. The known asthmatic didn't make it to the hospital alive: police reported that while in transit, Garner had a heart attack that killed him. After the incident, Richmond University Medical Center suspended four employees. Officer Daniel Pantaleo went on "modified assignment"; he'd violated NYPD rules just by putting Garner in a chokehold. Though investigators determined that Garner's death was a homicide, the Los Angeles Times reported that the local grand jury did not deem it appropriate to indict Officer Pantaleo. New York City settled with the Garner family for $5.9 million; Richmond University Medical Center also settled, but they did not make the amount public. A federal grand jury investigation followed, and, according to NPR, it started hearing evidence in February.

Since Garner's death, Carr transformed into an activist. The Wall Street Journal reported that she frequently participates in protests against police brutality and tells her story during school visits. Now, she's become one of the most powerful voices in the fight for justice and reform following killings of unarmed African American men by officers. After the deaths of Philando Castile and Alton Sterling, she told NPR that it's essential to fight through the grief and speak out in order to build and sustain momentum for the movement:

And those families - please keep awareness out there. Don't let it die because that's what they expect us to do. Oh, this - now it's headlines. Tomorrow, it'll be yesterday's news. Never let it become yesterday's news because to them, it's a headline. To us, it's our lives.

Carr endorsed presumptive Democratic nominee Hillary Clinton with a written statement on Clinton's campaign website in January. She said that Clinton's apparent commitment to developing strategies for decreasing gun violence and fighting injustice earned her support:

Along with too many others, Eric’s death has forced our country to confront the effects of police brutality. We’ve got to do something about the violence in our communities—especially gun violence—and the racial and economic injustice that’s connected to it.

Carr is poised to offer a powerful message in support of Clinton in Philadelphia, but Americans will likely hear her voice long after the DNC ends. As Carr told Clinton campaign team members, "I was thrown into this, but I’m going to stay the course." Carr seems to be confident that Clinton is the presidential candidate who will stay the course with her.