Teenage girl praised by Joe Biden, Kamala Harris for presenting key evidence in George Floyd's murder trial

The teenager who filmed George Floyd's murder is being celebrated by his family and politicians who say her footage is likely "the only reason" his killer was convicted.

Darnella Frazier was 17 when Floyd was murdered in May 2020 by Minnesota police officer Derek Chauvin 

She used her phone to record as Chauvin knelt on Floyd's neck for nine and half minutes, ignoring his pleas that he couldn't breathe. On Wednesday, Chauvin was  found guilty of second degree unintentional murder, third degree murder and second degree manslaughter.

Her footage featured heavily throughout the trial, of which Frazier was a key witness.

Recounting what she saw, the teenager said she told her nine year old cousin to go into a nearby store, as she didn't want them to witness what was happening.

"A man terrified, scared, begging for his life," she said.

"It wasn't right. He was suffering. He was in pain."

Her footage showed a drastically different account to what the Minneapolis police gave, which was handed out as a vague media release blaming a "medical incident" for Floyd's death. 

"On Monday evening, shortly after 8pm, officers from the Minneapolis Police Department responded to the 3700 block of Chicago Avenue South on a report of a forgery in progress. Officers were advised that the suspect was sitting on top of a blue car and appeared to be under the influence," it said.

"Two officers arrived and located the suspect, a male believed to be in his 40s, in his car. He was ordered to step from his car. After he got out, he physically resisted officers.

"Officers were able to get the suspect into handcuffs and noted he appeared to be suffering medical distress. Officers called for an ambulance. He was transported to Hennepin County Medical Centre by ambulance where he died a short time later.

"At no time were weapons of any type used by anyone involved in this incident."

Without Frazier, that account may have been taken as truth - a point stressed by US Vice President Kamala Harris.

"Because of smartphones, so many Americans have now seen the racial injustice that black Americans have known for generations, that my parents protested against in the 1960s, that millions of us – Americans of every race – protested against last summer," she said.

President Joe Biden said decision to film the murder was one of several "extraordinary" factors that led to Chauvin's conviction.

"For so many people, it seems like it took a unique and extraordinary convergence of factors: a brave young woman with a smartphone camera; a crowd that was traumatised; a murder that lasted almost 10 minutes in broad daylight for the whole world to see; officers standing up and testifying against a fellow officer instead of closing ranks; a jury who heard the evidence and carried out their civic duty under extraordinary pressure

Such a verdict is much too rare."

Philonise Floyd, George Floyd's brother, also thanked Frazier for her part in the conviction, saying without her footage, his brother would have been forgotten. 

"Because without that, my brother just would have been another person on the side of the road left to die."

Floyd's aunt Angela Harrelson said the footage "meant everything" to the case.

"Without her video, I mean – that video meant everything. And I commend her. She was so brave, because she held that camera for nine minutes and 29 seconds."