Amanda Alvear posted a video of her night out on her Snapchat story only moments before the armed killer burst into the nightclub Pulse in Florida.
It is the first footage to emerge from inside the nightclub with Amanda having since been confirmed as one of the 50 fatalities.
Initial snaps show Amanda having a good time with friends before the camera turns to her face.
Loud gun shots can then be heard in the background before the snap finishes.
Amanda’s best friend, Mercedez Marisol Flores, has also been named as one of the victims.
Amanda’s sister, Ashley Velez, paid tribute to her, saying: ‘I love you baby girl. You were and will always be my baby sister. I’m so heartbroken.
‘You could make anyone’s day with the smile of yours.’
The 26-year-old lived in Davenport, Florida and was a nursing student at the University of South Florida and worked at retail store Target.
The gunman, who has since been identified as 29-year-old Omar Mateen, was later gunned down by a SWAT team who reportedly used explosives to distract him when he took hostages.
He reportedly pledged allegiance to ISIS before carrying out the attack.