Her motivations were simple enough. You could even call them pure.

“It wasn’t right,” said Darnella Frazier, who was 17 last year when she saw George Floyd pinned under a Minneapolis police officer’s knee. She said that to the jury last month as she testified in the murder trial of that former officer, Derek Chauvin.

No, Darnella, it wasn’t right, a Hennepin County jury agreed on Tuesday, finding Chauvin guilty of second- and third-degree murder as well as second-degree manslaughter.

After so many previous instances in which police officers were acquitted of what looked to many people like murder, this time was different. And it was different, in some significant portion, because of a teenager’s sense of right and wrong.

Call it a moral core.

Darnella Frazier, who filmed the viral video of the arrest, said March 29 that she saw George Floyd “suffering” and in “pain.” (The Washington Post)

On May 25, while taking her younger cousin on a stroll to get a snack, the high school student observed a struggle between a Black man and White police officer. After ushering the child into the convenience store, Cup Foods, Frazier stayed on the sidewalk and started recording.

We’ve seen the images of her there on the scene in her loosefitting blue pants, her hoodie and her flip-flops, eventually joined again by her little cousin in a mint-green shirt that read “Love.” Frazier just stood there, resolutely, holding her phone. Later, she posted a video clip of about 10 minutes to Facebook.

That video clip, now seen millions of times around the world, was a powerful, irrefutable act of bearing witness.

The video, showing nine minutes and 29 seconds of Floyd gasping and ultimately drawing his last breath under Chauvin’s knee, was something that couldn’t be explained away.

The video became what one legal network legal analyst, Sunny Hostin, called “the star witness for the prosecution.”

In conversation with ABC’s David Muir last week, Hostin called it “the strongest piece of evidence I have ever seen in a case against a police officer.”

Over the months that followed Floyd’s death, Frazier hasn’t given any speeches. But she gave an interview or two. And every time I’ve seen or heard her quoted, I’ve been struck by a few things.

She is soft-spoken and understated, not trying to draw any particular attention to herself. She may have been troubled by the experience but remains clearheaded about what she saw and what it meant.

On the witness stand late last month, she also had this to say about Floyd, whom she did not know:

“He was suffering. He was in pain. . . . It seemed like he knew it was over for him. . . . He was terrified.”

And like so many of the other young Black people who took the stand in the trial, Frazier could see in him her own family members. In some way, he represented them: They were, she said, her father, her uncle, her brother.

A few months ago, Frazier found herself accepting an award from PEN America, the free-speech advocacy organization. Filmmaker Spike Lee presented it to her in a virtual ceremony noting that the award was given to recognize courage. Luminaries including Rita Dove and Meryl Streep offered kind words to the young woman from hundreds of miles away. Law professor Anita Hill — famous for accusing a soon-to-be Supreme Court justice of sexual harassment nearly 30 years ago — spoke to Darnella Frazier, too.

“Your quick thinking and bravery under immense pressure has made the world safer and more just,” Hill said. Like the others, Hill added: “Thank you.”

Again, Frazier was quiet but centered when she spoke: “I never would imagine out of my whole 17 years of living that this will be me,” she said. “It’s just a lot to take in, but I couldn’t say thank you enough.”

But it was Frazier’s early interview with the Minneapolis Star-Tribune that has most lingered in my mind, even more than the testimony she so movingly delivered from the witness stand. She explained that she felt compelled to hit “record” because she was seeing something completely unacceptable.

She may have felt helpless. She couldn’t pull Chauvin off Floyd’s neck, but this was something she could do.

“The world needed to see what I was seeing,” she said.

We saw it, Darnella.

READ MORE by Margaret Sullivan:

For more by Margaret Sullivan visit wapo.st/sullivan