Darnella Frazier was taking her nine-year-old cousin to buy snacks at a local corner store when she saw a police officer hold down a Black man with a knee to his neck.
She instinctively pulled out the phone in her pocket and pressed record.
In the next ten minutes, not only did the teenager witness the man draw his last breath, but she also broadcast it to the world in a video that sent hundreds of millions of people into a righteous rage.
The world learned his name was George Floyd. His death spurred the largest civil rights protest in decades.
At the time, the then-17-year-old told the Star Tribune that she pressed record “as soon as I heard him trying to fight for his life” because: “The world needed to see what I was seeing. Stuff like this happens in silence too many times.”
Ms Frazier added: "My video proves what really happened."
Watch: Rev. Al Sharpton at George Floyd's memorial. Post continues below.
One year later, the now 18-year-old was among the first witnesses to testify for the prosecution side in the trial of George Floyd's death.
During her testimony, she recounted witnessing the murder, saying Mr Floyd was "terrified, scared, begging for his life”.
“When I look at George Floyd, I look at my dad. I look at my brothers, I look at my cousins, my uncles, because they are all Black,” she said through tears.
“I have a Black father. I have a Black brother. I have Black friends. I look at how that could have been one of them."
Ms Frazier went on to explain how his death has haunted her in the past year.