Fatima Khan, 21, posted a video of Khalid Safi, 19, as he lay dying after being stabbed with a screwdriver by Raza Khan, 19, in Acton, west London, in December 2016.
"That's what happens when you f*** with me," she captioned the Snapchat video.
The trial at the Old Bailey heard Khan — who was nicknamed the "Snapchat Queen" by her friends because of her social media addiction, visited a Costa Coffee shop near North Acton underground station with Mr. Safi around 5pm on December 1, 2016.
'Happy' Couple
Eyewitnesses said the couple seemed "happy and smiley" but Khan was preoccupied with her cellphone.
At around 6pm Raza Khan arrived and immediately went over to the couple and began stabbing Mr. Safi, who was originally from Afghanistan.
"She returned to the scene after Raza Khan had inflicted the fatal wound and videoed Khalid Safi as he lay dying in a pool of his blood on the pavement," Ms. Bex told the trial.
She then posted the video on Snapchat, along with the sarcastic remark.
'Mr. Safi was the on-off boyfriend of the defendant, Fatima Khan, and the prosecution case is that he was killed by a rival for her affections,' prosecutor Kate Bex QC had told the jury.
Khan was acquitted of murder and will be sentenced on Monday, July 30.
Killer Is On The Run
Raza Khan is on the run and may have left the UK,
A £5,000 reward for information leading to his arrest has been offered by the charity Crimestoppers.
"My brother was very young, only 19 years old when he was killed in the street. He came to London for a better life but was killed for no reason. I want to appeal to anyone, especially the Afghan community who has any information to come forward and speak to the police," Mr. Safi's brother Shamsullah said last year.