The terror attack on Orlando's Pulse nightclub was captured on video by a young woman who was posting on Snapchat when the shooting began.
Amanda Alvear, 25, was posting videos of herself and her friends drinking and dancing, but the final one contained the chilling pops as terrorist gunman Omar Mateen opened fire.
Alvear was later confirmed to have been one of the 49 fatalities. More than 50 people were injured, with five victims said to be in grave condition.
In the video, Alvear does not appear to realize what is going on. She looks confused as more than a dozen shots are heard before the video ends.
Many clubgoers reported afterwards that they did not immediately realize the pops were gunfire amid the loud music.
This is the only video to emerge from inside the gay club during the attack.
Alvear's friend posted video of the Snapchats to Facebook, writing, "Found out through Snapchat my friend Amanda Alvear was there at Pulse last night. Tried calling and texting and still haven't gotten a reply.”
Mateen was killed about three hours later in a gunbattle with SWAT officers who stormed the building.
Watch the footage above, via TMZ.